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>>Male Presenter: Jeff Potter is one of us. He's a geek. He studied Computer Science at
Brown, done his time in a cube at a start-up. He's organized BarCamp, a Boston-based technology
unconference, for and by attendees. And today, we've asked him to come talk about his other
geek hobby, food.
Jeff's book, "Cooking For Geeks," which some of you might have found on your chairs, sprung
from his passion for food. With no formal culinary training, Jeff wrote a book about
food. It's not really a cookbook. It's got a whole chapter on food-borne illness--
[laughter]
that he's conveniently broken into two sections, parasites and bacteria. But you can't really
classify it like that.
Similarly, it's not really one of these detailed recipe *** books where they show you the
recipe and then they have beautiful pictures 'cause he dug a bit and devoted a number of
pages on Twitter recipes and publishing in a couple of hundred characters a recipes.
So, it's really a book about food that appeals to people who like to overanalyze, kinda like
us. All right. I'm happy someone's written a book about food for people like me. I'm
hoping today he'll answer my question about why we call them "cookies" and not "bakies,"
when clearly they should be called bakies. And--
[laughter]
>>Jeff Potter: AT&T burn.
[laughter]
>>Male Presenter: And with great pleasure, I'd like to introduce Jeff Potter.
>>Jeff Potter: Thank you.
[applause]
Thanks for the great kind words. I hope I live up to the hype. And of course, there's
nothing better for a geek than a Venn diagram. So, I get asked a lot, "What's a geek?"
And I'm like, "This is the answer to what a geek is." Note the [inaudible] bit is not
included in the set of the things that make a geek up. And for me, that's like really
important to people who invariably think pocket protectors and all this other stuff. But it's
not what it's about.
For me it's really about curiosity. And as Jeremy was saying, for me, whether it's in
front of a computer or in the kitchen, it's really the curiosity about how things work
that gets me excited. And so, when it comes to cooking, it's exactly the same thing. How
does this thing that we do in the kitchen, how does it actually work?
Why do we do the things we do the way we do them? And once you know those things, what
can you do that's fun, new, interesting, or just plain delicious? Continuing the theme
of Venn diagrams, figuring that it's Google, I figured the Google Venn diagram generator
was appropriate.
You know, pointing at things like Windows and Apple. You can see there's some interesting
traits like, I guess everyone knows why Apple is so popular because people don't seem to
search for it. "Why is Windows so popular?" comes up a lot. Hey. Here's another one which
is a little more interesting.
It has chefs versus geeks versus bakers. Geeks clearly don't wear white. I don't quite get
the "like bacon" bit. I would think it would be under "cooks" as well, but you know. Then
the last one: Science, cooking, and food. And the interesting thing for me is all three
of these things are important.
And I thought it was actually nice to see that come up. So, a bit about science. And
it's always fun to talk about science in the context of dead white dudes. So, I present
to you three dead white dudes: Aristotle, Newton, and Einstein. And the thing that these
three guys all have in common is they all came up with models of gravity.
And in science, models are really, really important. Aristotle's model was really, really
simple. He basically sent things to fall at a rational place. So, the drop that falls,
I don't know why it didn't fall in my mouth, but it's a really simple model and it's not
very good.
In the 1800s, we start getting better models. Galileo came up with something that describes
basic high school physics for gravity. It's still taught in high school today. It's pretty
good as a model goes. But it's not actually perfect. It doesn't actually describe Mercury's
orbit around the sun, rather famously.
And you actually can't describe that with that law. You have to get an even better model,
something that Einstein came up with, the Theory of Relativity. And that actually accounts
for Mercury's orbit around the sun. The point here is that with better models, you get better
predictions.
And it's true in all sciences and it's true in the kitchen. So, let's actually talk about
a model of cooks, types of cooks. Right now, your model of types of cooks is probably pretty
simple. But how many types of cooks are there? So that's two types. People who like to cook
things and people who like to bake things.
But it's actually a very simple model. It's Ancient Greece territory in terms of like,
"Yeah, this sounds good." But it doesn't actually really describe what's going on in the kitchen
that well. So, the researcher down at Cornell got some data, looked at thousands of cooks,
home cooks, and asked them lots of questions and did a factor analysis.
And he came up with this five-factor model that describes five different types of cooks
that describe most types of cooks. And luckily, he came up with a quiz for it. So, here's
a quiz. This is a really simple quiz. The way we do this is just to keep track of what
letter you answer most often.
And whatever that letter is in the end, that's your type. It only accounts for about 85 to
90% of the population. And given the people in this room, I have my guesses about how
this is gonna go.
[laughter]
I will say that under normal populations, there's a roughly 20% split between all five
types. So, keep that in mind when you go through this. First question: When I cook a meal,
I typically dot dot dot.
If anyone needs me to read these off, holler. But if you can see them great.
[pause] Everybody good? Should I go to the next one?
OK. Some of my favorite ingredients are. That thing from the kitchen around the corner.
They did the right cookies. Anyone have Dayquil for me?
Unusual tea. It's not unusual to you because of cultural things, then it’s not an unusual
ingredient. Shall I go to the next one? Howdy. In my free time I like to. OK, I know you
guys are like, "What free time?"
[laughter]
Next one? My favorite things to cook are. Jeremy, are you A on this?
>>Male Presenter: Mmm.
>>Jeff Potter: Looked good.
>>Male Presenter: Thank you.
>>Jeff Potter: Your recipe. Delicious.
[pause] Are we good? OK. And the last one. Other people
describe me as. And F is a joke. I put that in there in a previous talk. Don't actually
answer F. If won't do us any good.
[laughter]
>>Male Audience Member #1: What about none of the above?
[laughter]
>>Jeff Potter: This only fits 90% of the population plus or minus delta. So, I'm curious to see
a show of hands. Who here said "A"? So it’s like, let's see, five or six? "B"? Only five
or six. "C"? Probably about seven. OK, "D"? Yeah, about 40&, like half the room. "E"?
Two. OK. That's cool. So here's what these things mean.
The researcher who did this was Dr.Brian Munson down at Cornell and he basically looked at
types of cooks. There's giving types of cooks, so people can basically, they basically wanted
to express their affection through baking. So they should all show up at work with a
box full of gingerbread cookies.
And what they're really saying is "hey, I love you guys." Then you go, "Thanks. That's
really cool. I like them." Thanks, Jeremy.
[laughter]
>>Male Presenter: I love you guys.
[laughter]
>>Jeff Potter: It's like next time someone shows up with a plate of brownies, that's
where it's coming from. Healthy. This is somebody who'll do it for steamed veggies, brown rice,
fish, chicken.
To them food is really about nutritional value, taking care of the body. Methodical. This
is something you can give them a recipe and they will nail it perfectly. It'll come out
exactly like a recipe says, but if they're missing like one ingredient, like, they don't
know what to do.
And Innovative. This is the type of person who basically like maybe reads a couple recipes,
looks at some TV shows, like walks into the kitchen and throws stuff into a pan and it
comes out. He doesn't have a good time doing it. And for them this is kind of like, "Hey.
I'm just goofing off, playing and seeing what might happen."
And that's really how I like to cook. And then finally, this Competitor type. This is
somebody who like, for them cooking is almost an act of expressing who they are as a personality.
Grilling, things that are a little bit chest-thumping type things. That make sense? It's totally
cool.
But for them it's as much about that act of cooking and doing that in a competitive realm.
So, that all said, we started with a really simple model. It's like there's two types
of cooks. But here's a better model. And once you have a better model, you can start making
better predictions.
So, you can imagine a couple, or maybe somebody who is really health-driven married to somebody
who is all about expressing affection. So you know, the girlfriend makes for the boyfriend
a plate of brownies, saying, "Hey, I love you." And the guys like, "Oh my God, this
isn't fish and veggies. Like Oh, my God, no!"
And you can just see this conflict that comes up around food. And food is such a thing.
You're laughing about this, but only because this is a true person?
[laughter]
You have this very pained look. Now with this better model, you'll understand what's going
on.
[laughter]
She looked at me like, it's really powerful to have that better model because besides
breaking ground on the front row of an audience, now we can talk about it. It's not an offense.
So, that whole bit of a model is really, really powerful. Science, in general, really does
rely on these two thing, theory and data. And they say this a lot. And a lot of people
go, "Yeah, yeah, yeah, of course. I understand this in science." But they don't think about
it in the context of the kitchen.
Without your data, your theories are really no good. You don't know if they're true or
not. Without your theories, well, you just compile data and you can't predict new data
points that you don't have in your set of observations. Same thing is true in food.
Here is a model of an equation for knowing when meat is done being cooked.
[laughter]
I can't read this. I confess I am not a theory guy. My background is much more on the data
side of things. So, when it comes to the kitchen, all I think of are data. So, I'll do things
like this. I'll go into a kitchen, take a lump of chocolate-chip cookie dough, throw
a probe into it, throw it in the oven and see what happens.
And start recording data. So, what's your model right now tell you about what happens
to a lump of cookie dough when you throw in the oven? It cooks. I had someone go " it
turns into a cookie."
[laughter]
[You open the box and put in the dough and the cookies come out. So if you put an apple
in there, a cookie is just not coming out.]
[laughter]
So, let's look at cookie dough. It's kind of interesting. So, after I put this probe
in, this little light out here you barely see. It's actually little probe thermometers,
kitchen, 30 dollar thermometers we've got at home.
So, around 92 degrees they begin to spread out and do that thing that you were saying.
That's the temperature which butter begins to melt. So like, right. OK. This makes some
sense. There's some structure holding this mass of dough together and that structure
starts to go when butter starts to go.
Isn't that cool? Around 212 degrees, the edge of the cookie begins to set up. It starts,
again at 212 degrees, an obvious number, the boiling point of water. And the edge of that
cookie begins to steam up. It's also around the temperature in which a lot of starches
and things like flour begin to actually like melt and do their thing as well.
Then at around 310 degrees, the outside of this cookie begins to turn light brown. Any
guesses what's happening around 310?
>>MALE AUDIENCE MEMBER #2: Condensation.
>>Jeff Potter: A good guess, but not the right guess.
>>MALE AUDIENCE MEMBER #3: Maillard.
>>Jeff Potter: Yes. Who said Maillard? An extra gingerbread cookie to the man in green.
[laughter]
A Maillard reaction is a breakdown between proteins and simple sugars. Basically, these
two things break down, form hundreds of new compounds, some of which are brown, some of
which smell really, really good and we happen to like.
And if that doesn't do it for you, think about taking a slice of bread and toasting it. That
toasted smell that you get? That's the Maillard reaction. And it's really important in cooking
because it brings a whole set of flavors. So, think about things like brussel sprouts.
Brussel sprouts are universally boiled and universally hated because the flavors kinda
bland. If you quarter them, throw some olive oil, some salt on there and put them under
a broiler, you get some nice toasted, rich, brown outside that help us bring the flavors,
the Maillard reaction.
And that's responsible for a lot of flavor in foods. And once you start realizing it's
a temperature-dependent reaction, you now realize right, cooking methods that don't
get that hot won't trigger that reaction. So, you have to get things that hot to get
that reaction.
When we think about steaming or boiling something, well, it's gonna bring a loss of flavors.
Then at around 356, 360, somewhere in that territory, our cookie gets turned even darker
brown. And this is from caramelization, as you guys were guessing earlier.
And this is pure breakdown of sucrose and other sugar molecules. This temperature I'm
giving you is for sucrose, specifically. Basically, it's just the sugar molecule itself is decomposing
and then forming hundreds of compounds again, some of which are brown, so they smell good.
And it's surprising in hindsight for me, looking at the book and working on it, how long it
took to understand some really like, basic "duh" type things. Caramelization has nothing
to do with melting. This happens if sugar melts right at the same temperature point
that breaks down, decomposes.
Fun fact. Sugar melts at around 367, actually 377, so those after 367. So you can actually
calibrate your oven using sugar, just like you use on ice cubes. You know how your freezer
is above 32 or below 32. Same thing with your oven. If you put sugar in your oven at 350,
it shouldn't melt.
If you leave your oven at 375, it should melt. You can start looking at recipes and say,
"Hey, some recipes call for things being cooked at 325 or 350. Other recipes at 375." There's
this nice, like break point between these two sets of temperatures and that is the chemical
reactions that sugar goes through for both melting and caramelization.
So, here's a nice little visual proof of this. I just took some sugar dough. It's kind of
hard to see them on the projector. But basically, I just took some sugar cookie dough and baked
it at different temperatures. And you can see there's this really nice difference between
that 350 to 375, where it starts to get brown.
And note, on these temperatures, they are not exact points. These are Maillard reactions.
So like, caramelization picks up the hotter you go, but it's not really visibly occurring
until around a little bit north of 350. So, there's a model and then your simple model
of cookie dough to cookie, right?
Next time you're going to make cookies, you can think about things like, "Hey, do I want
these a deep brown?" In the case of a chocolate chip cookie. Or, not so brown in cases like
a sugar cookie or an oatmeal cookie. Same thing is true with meat. Another model for
you. When you cook meat, what happens? Bueller? Bueller?
>>MALE AUDIENCE MEMBER #4: Brown, scalded.
>>Jeff Potter: Browned.
>>MALE AUDIENCE MEMBER #5: It like burns and the inside stays cold.
>>Jeff Potter: Do what?
>>MALE AUDIENCE MEMBER #5: The outside burns and the inside stays cold.
[laughter]
>>FEMALE AUDIENCE MEMBER #6: It turns brown and when it breaks down you get texture.
>>Jeff Potter: Yes. You get textural breakdowns when a number of the proteins denature. And
specifically, at least in the papers I've been able to find, it seems like there are
different proteins that are responsible for this, some of which we happen to like being
denatured when cooked, and some of which we happen to like being in a native, uncooked
state.
Specifically, the two are myosin and actin. Different types of meats have different variants
of these proteins when temperatures vary a little bit. But essentially for a thing like
steak, it looks like right at 122 degrees one of these proteins, myosin, begins to denature.
And in the process of denaturation, changes its texture, changes the way it tastes and
the way we perceive it. And we happen to like that change. And if you look at another protein,
what we call actin, it begins to go somewhere around 150. And unlike myosin when it denatures,
it changes its texture and gets tough and dry and not so delicious.
If you look at things like medium-rare steak, it's at this temperature point, 135, 140,
where you basically mean one of those proteins is cooked and another one uncooked. So suddenly,
it's like, "Oh, right." This thing is about the particular reactions that are occurring
at particular temperatures.
It's not so much about the time you cook your meat at whatever temperature you're cooking
it, it's really the actual temperature of the meat in itself AND what it comes up to.
So, when we take the piece of meat. Let's say you take a steak tip and drop it into
a pan, you get something that looks kinda like this.
Again, it's kinda hard to see in the projector. Basically, there's this grainy adundant square
. I've done this. Where it's kind of, well this particular example is basically rare
in the middle. Looks like medium-rare and you have well-done out here and notice the
outsides brown from the Maillard reaction we were talking about earlier.
So, one question to I get asked a lot at this point here, well, why are we told always to
cook things at 165 degrees? I mean, if the proteins in here are really ideal at 135,
140, like why is it we're constantly hammered with this "Why 165" number? And the reason
for this is this.
Salmonella, another food-borne illness, definitely not a fun thing to come down with. And one
of the main reasons we cook food is that it's safe for us to eat. The standard rule is actually
given in food safety, this thing called the danger zone. It basically says don't hold
food between 40 and 140 for more than two to four hours.
It depends upon what state you’re in. The laws of food safety are actually state by
state. But essentially in that time window, in that temperature range, then you start
running into problems. Now, you'll notice this nice, little square I have here is a
simple model of what's going on.
And there's a little dotted line, which is actually a better model of what's really going
on, which is essentially that bacteria like to multiply at different temperatures and
different rates. So it happens that salmonella reproduce best at body temperature. And what
food safety people are concerned about is the quantity of these pathogens that are present.
It's not really like your food is either safe or unsafe, it's really a probability how unsafe
is it. And that's kind of, you know, a little icky when you think about it at first, but
once you understand it's really about probability and odds, you can start understanding how
to mitigate those risks and actually correctly taking the [inaudible] and start doing some
fun things.
So, you don't have to just take my word for it. In terms of things like cooking foods
below 140, you can actually do this. Even according to the people that set these guidelines.
So the Food Safety and Inspection Services has a table that says here's how long you're
supposed to cook food at various temperatures.
If you wanna cook your chicken at 136 degrees, you can do that. You just have to hold it
at the temperature for over an hour to make sure it's properly pasteurized. So, it's really
about reducing the quantity of pathogens that are present to a sufficiently safe level,
such that it's not likely to hurt you.
Now, why would you wanna do this? Well, we were talking about myosin and actin a few
minutes ago and it comes to this texture of the proteins. If you can get something to
a point where it's safe to eat, but you haven't denatured the actin, well, you're not gonna
say it's delicious, just safe.
And that's always the end goal. So, simple model. Cook your meat to 165. And by meat,
it's really usually poultry. The better model is really 140 degrees is OK as long as you
hold it correctly to pasteurize it. So, once you do this, you can do fun things like this.
You'll see the piece of meat on the right is basically medium-rare. The whole thing,
center to edge. You also notice the outside has no brown crust on the outside 'cause it's
got no Maillard reaction. Any guesses as to how I did this?
>>Audience Members: Sous vide.
>>Jeff Potter: Yeah. I asked this like, two years ago and people would be like, "What?"
Yeah. This is called sous vide cooking. It's a really simple concept. It basically says
hold your food in an environment that's at the target temperature that you want to cook
something to.
So if you take a piece of meat and you're wanting that steak to be at say, 140 degrees.
Instead of putting it into a 300 degree oven, you can put in into an environment that's
140 degrees. And eventually, it'll go up to a temperature of 140 degrees. It works great
for eggs. Hey. No worries. Are there any gingerbread cookies left?
>>Female Helper: No, we don't have any here.
[laughter]
>>Jeff Potter: So, it really comes down to the sous vide stuff that it's really about
the temperature that you're trying to get your material to. It can be your target temperature.
And the benefit of this is that you can't overcook things because you're not talking
about an environment that's hotter.
So if you've got that actin protein in meat, for example, it doesn't really begin to go
until 150. Well, if you put it in an environment that's 140 it never gets to be 150. That reaction
never triggers. So, you can't overcook things. Eggs are a great example. This is my set-up
at home.
This is called immersion recirculator. It's basically a piece of fancy lab gear that keeps
water at a particular temperature and it's got a little propeller that agitates it, more
on that in a little while. But the eggs themselves work out really, really well this way. Think
about the temperatures that are involved in egg.
You drop that egg in a regular cooking situation into a pan of boiling water and it does this
and gets hotter and hotter, right? In like five or seven minutes, then you basically
pull it out, somewhere right around here. Right in the really, really narrow band that's
the ideal temperature range for eggs.
And hopefully, you timed it right. About 144 and 158 refer to the two temperature points
at which proteins in eggs begin to denature and the upper limit where most of them actually
set. So a really good soft poached egg is somewhere in-between that range.
And depending on how well you like your eggs set, it's going to be somewhere between there.
There's 15, 16 different types of proteins in these eggs and they all denature in that
range. This is the sort of thing where you can have fun playing with it one degree at
a time just to see what your perfect egg is.
The thing about doing it with sous vide style is that you set your temperature of your bath,
put your egg in, and the egg just ramps up in temperature and finally just reaches that
ideal temperature point, but it never over cooks. So you get this egg that is essentially
perfectly soft poached and just sits there for a couple hours.
So, if you're trying to cook brunch for 30, 40 people, you just put the bucket out, put
your eggs in, set the temperature and walk away and forget about it. And they won't ever
overcook. The key to making sure that--. The one thing that I want you to really understand
to hammer home is that it's the temperature that's important here.
Time is just a proxy for temperature. When you put those cookies in your oven and you
time them for 12 minutes, well it's really about how long does it take for that mass
of dough to come up to a certain temperature at the temperature of your oven. But it's
really the temperature of the actual mass that matters.
So here's a photograph of an egg that had been cooked this way. It's kind of hard to
see, so here's a video of it. The other cool thing I was doing things this way was this
one layer of egg on the outside that doesn't actually set up until a higher temperature.
So the egg just falls out of the shell when you do this. It was like, totally awesome.
[laughter]
And you'll see coming on the screen here in a minute, you can see the texture. The yolk
and the white have almost the same texture. They're both mayonnaise-like consistency when
cooked at a certain point.
There you go. Yeah, and they're delicious. I mean like, if there's one thing you can
go home and try is sous vide eggs. Definitely hands down. So this is a piece of gear that
I have. It's called an immersion recirculator and it's expensive. Three, four years ago,
this was the only way of doing it, but there are now better ways of doing this.
There a consumer device out called the Sous Vide Supreme. They're like three or four hundred
dollars. If you've got counter space and the cash, it's certainly very easy and they look
nice next to your other stainless steel appliances.
[laughter]
But if you're like me, a pair of wire cutters--.
[laughter]
This works. It works very well. Just say your crock pot or any slow cooker, interpose on
the power supply. Rig up your own thermal coupler and drop it in the thermostat controller
and you're good to go.
And it's actually easy. And I get questions a lot of times about, "Well, there's no circulator.
There's nothing to agitate the water bowl." For whatever reason it seems that, at least
for the stuff I've done in the slow cooker, the heat source in the bottom over a large
enough area.
There's really no gradient inside the container. You don't have to worry about it so much.
One other thing I neglected to mention earlier. When you pulled that piece of meat out it
didn't have that brown outside. There was no Maillard reaction on that. And that's one
of the really good key characteristics of a really good steak.
So, what we do is after you take it out of the sous vide environment, you then drop it
into a pan. You sear the outside. So you're basically still getting that reaction outside,
but you've taken the two reactions, the external temperature and the interior temperature,
and you basically are controlling for them independently of each other.
If you don't have any kind of race the outside temperature and the inside temperature. So
you were saying earlier you're always like, overcooking the outside and the middle is
rare.
>>MALE AUDIENCE MEMBER #5: Yeah.
>>Jeff Potter: It sounds like you're barbecue is too hot. So, try cooking it at a lower
temperature. That would be my guess. So, kind of in summary. I mean, if there's a high-level
couple of bullet points you'll hopefully remember tomorrow or next week, this is simple models,
simple predictions that will help you recover when disaster strikes.
Better models, better predictions. And really, for me a lot of it comes down to just being
curious in the kitchen. If you walk into the kitchen and you're like, "Hey, how does this
actually work? What's going on here?" And you're not sure. Well, do an experiment. I
mean it's really easy to gather data in your kitchen.
And when you're talking about cookies and you're not sure about the difference between
melted butter versus room temp or even fridge temp butter when you're making your cookie
batch, just take two batches and do them side by side and see what the difference is.
'Cause you're gonna learn a lot more about what's going on in that process by actually
trying it. And you can sit there and have lots of guesses, but until you actually try
something and see what comes out, well, you're not gonna really be sure.
There's this great quote that I saw years ago that really brings home for me a lot of
these things. "In theory, there's no difference between theory and practice. In practice,
there is." The reason for this is there's always a delta between what your theory predicts
and what really happens in your life.
The thing is with a better model, that delta gets smaller and smaller. And so, there always
will be a difference, but hopefully by understanding some of the science that difference will be
easier to understand even smaller. So with that, I figured that it'd be much more fun
to open this up as a conversation and talk about questions you guys might have.
Hopefully I've given you lots of ideas and being aware of things to talk about. But I'm
totally happy to hang out for the next half hour and answer questions and strategize a
little bit about questions you might have and how to figure out answers about it. So
with that, thanks.
[applause]
Jeremy.
>>Male Presenter: You mentioned that people preferred tastes as the proteins changed at
different temperatures. Is that evolutionary? I mean, is that like, have there been studies
done to show that we like it tasting better because it has less bacteria, therefore we
live longer, blah blah blah blah blah?
>>Jeff Potter: I don't think that that's been done. And I don't know how you'd do that.
But textural preference of meat stuff is definitely a personal preference based on what you grew
up with.
>>Male Presenter: OK.
>>Jeff Potter: So it's the reason why--. If you look at older people, they tend to actually
prefer their meats cooked well done or well. They don't like that medium rare texture.
A lot of it comes down to as we learn more about food safety, we've relaxed the rules.
So actually just recently in the last few months, it's now considered safe to cook your
pork to 145 as opposed to 165. That's because trichinosis, which was a concern in pork originally,
it's basically not in our meat supply, at least here in the US. It's just the same thing
with meat texture stuff where it's like, well, two generations ago, people really cooked
it to make sure they weren't gonna get anything.
Now it's actually OK to go even colder. I don't know about being able to show it biologically,
evolutionary. I think it's more cultural than anything. Good question though. Thank you.
>>MALE AUDIENCE MEMBER #7: Your salmonella food safety graph, I noticed the dotted line
was still on zero below freezing.
>>Jeff Potter: Yes.
>>MALE AUDIENCE MEMBER #7: How far below freezing does it have to go before it's actually zero?
>>Jeff Potter: Pretty gosh darn cold. For things that deal with food safety, that dotted
line really isn't so much of a concern, but spoiled bacteria, it is. This is why if you
put things in your fridge, they eventually go bad.
>>MALE AUDIENCE MEMBER #7: Right.
>>Jeff Potter: 'Cause they're, really it's something multiplying at that temperature
range. I don't know below freezing at what point it actually ceases to get, I think there
are some, but even at freezer temp it could be an issue, which is why the guidelines say
not to hold food in your freezer for more than six months.
I think there actually is some stuff that can come up, but it's such a slow rate that
most people don't get into product limits. That's a good question to look into more detail.
And the thing about that dotted line on the high side is that really, the highest temperature
hits 130 a little more serious, the next highest is at 122.
So, this is a cartoon line. Obviously, it's not specific bacteria. But the thing is none
of these things really multiply above 131-ish. So holding food at 140 is actually safer than
40. Think about it. So, 40, they can't actually multiply. They can't get around. This rate
is so slow that it's not really an issue with how to consume it.
But given the choice between eating beef stew that's been held at 140 degrees for six weeks
versus held at 40 degrees for six weeks? I'd take the 140 degree. 'Cause it basically,
at that point, it's clean, it's sterilized it, how long it's there.
>>MALE AUDIENCE MEMBER #8: In sous vide, though, you're bringing it up to the temperature much
more slowly--
>>Jeff Potter: Right.
>>MALE AUDIENCE MEMBER #8: which means it spends more time in that bulge of this curve.
>>Jeff Potter: Yes. That's a really good question which is this sous vide stuff where you drop
it in. And basically, you're dropping it in from fridge temperature and it has to traverse
this entire span.
And it takes whatever length of time. This journey is normally not a problem in sous
vide, because we normally portion the foods to individual portion size, and so the actual
food comes up to temperature pretty quickly. If you take like, let's make a number up,
like a six-ounce steak.
You drop it. And it's at 40 degrees. It's gonna get up to temp pretty fast. If you took
five pounds of chuck roast that's been frozen, like that's, like don't do that.
[laughter]
And the reason for that is that the center of that is gonna be between that 40 and the
140 for such a length of time, that depending on what your environment is, there's some
big huge variables in there that it's just gonna sit too long in a bad temperature.
I should probably add a little asterisks here and say things like steak or other meats that
are called WMULT, Whole Muscle Intact, the center of these pieces of meat are actually
sterile. In those cases, you really only care about the surface, 'cause we were at surface
contamination during butchering, slaughtering, transport work into the kitchen.
So, this is why it's OK to do things like take your steak, sear it outside and then
serve it rare. 'Cause even in the middle is essentially, in a rare case, even let's say
120 degrees, obviously well below that safety point. It's sterilized. 'Cause it hasn't actually
been contaminated.
So things like ground hamburger, though, where ground hamburger is all outside, that there's
no inside. I've secretly wanted to go to a food safety convention and like, serve hamburgers
and ask the people, "How do you want this cooked, medium rare?"
'Cause like nobody should want their hamburger cooked medium-rare because it's at a temperature
at which you haven't actually properly pasteurized and many pathogens there might be present.
I will note that you can properly pasteurize hamburgers to medium-rare using sous vide
So, that's where having a better system of models comes into play 'cause you can start
doing some fun stuff like not worry about organisms that might be present. Go for it.
>>MALE AUDIENCE MEMBER #9: You can presumably get away with it if you knew the meat was
ground immediately before you cooked it, too.
>>Jeff Potter: Yes. If you have control over the--. I mean, it also depends on what the
problem or the source of the contamination is at that point. I mean, yeah. If you're
grinding it yourself, you've got lots of control over everything.
>>MALE AUDIENCE MEMBER #9: If you sear the outside.
>>Jeff Potter: Yeah. If you sear the outside, then you have a completely sterilized grinder,
[laughter]
I mean, as long as it's clean, you're fine going in. But a lot of the food safety stuff,
it basically assumes the worst-case scenario. Let's just assume this piece of poultry is
infected with salmonella to the worst possible degree.
And then we need to reduce the log D, the term is log D reduction. We need to do a seven-fold
reduction. Only one in a million are going to survive after cooking that. Like, that's
the statement. That's the numbers they give you. So I mean, their concern is safety, not
taste and texture.
That's where the balance always comes into play. [pointing to audience member] In the
>>MALE AUDIENCE MEMBER #10: Sir, on the topic of sous vide taking a long time to come up
to temperature, has anyone in the sous vide community looked at a trick that, I think,
hunters used a lot in time where you say, "Oh, if I want some stuff that I dump in a
bath of hot water to be at a particular temperature, I approximate the stuff by room temperature
water and make the water extra hot so that when I dump it in, the temperature is, after
everything is said and done, is gonna be what we want."
>>Jeff Potter: This is a good idea and I'm sure it would help in theory.
In practice, when your container of water is this big and the food you're putting in
is already at 40 and we wanna make it 140 and it's not actually a problem being a food
to temperature criteria.
The bigger problem that does come up with sous vide stuff is once you get to temperature
the question is then what do you do with it? So, if you're a restaurant and you're doing
something that you're gonna bring up to temperature and you're gonna put it in the fridge.
And the next day, you're gonna take it and heat it back up. You're now traversing that
span, like three times. And it's the cumulative time that's the matter, unless you actually
properly sterilize it by the time you get it up to temp, which isn't gonna happen in
this case.
So in that case, there's a whole set of guidelines called HCAP. I can never remember. It's like
H-C-A-P, Hazardous Control and something Program. Basically it says if you sous vide stuff,
there's two methods. There's one that's cook/serve and the other one's called cook/chill.
With cook/chill, you basically need to cook it and chill it as fast as possible. Like,
dump it into an ice bucket, or ice and a little bit of water to get it down really quickly.
So, in those cases, you stop worrying about the temperature stuff and playing with how
quickly you can move the temperature back and forth.
But if you basically do what's called cook/serve, where you cook it and you put it on a plate
and you ship it out. I mean, like sous vide in restaurants is great. Because if somebody
orders a steak, you've got it in a plastic bag and it's in your sous vide tub. It's gonna
need some marinade in the bag so it's gonna taste good, too.
You pull it out. Slit the bag open. You sear for 30 seconds on a side, drop it on a plate,
and ship it out. Like, you don't have to wait for cooking because it's already cooked. So
cook/serve stuff is really easy to do at home.
Cook/chill stuff is, just make sure you get a cold enough bowl. There's a really good
guide online. Douglas Baldwin has this sous vide, a guide. You can just Google sous vide
Douglas Baldwin. You'll find it. Great page that details like everything down to like,
I mean, he's done a fantastic job of coming up with literature, of coming up with great
tables. So, that's where I point people to. Gotcha.
>>MALE AUDIENCE MEMBER #11: How does contamination and danger zone and such vary with vegetables,
>>Jeff Potter: Yeah. You're more likely to get food-borne illness from your veggies that
you are from your meats at this point. It's the number one metric. We don't cook lettuce.
If you think about all the salmonella outbreaks that have happened, like spinach, than things
where you're not actually adding heat to it. Wash your veggies. I mean, really. Wash your
veggies. I don't know if I answered your question.
>>Jeff Potter: Umm.
There's other things like acdity, pH, temperature, time. I don't mean specifically a container
my food is not a problem because I eat it faster than the bacteria will. Yeah.
cooked. They should be more worried about getting sick from veggies that have not been
you have any, is there any special procedure for properly washing your vegetables?
every Thanksgiving, it seems like it should be possible to sous vide your turkey in the
Oh, let's see. Long, rambling tangent. OK. Actin, myosin, another important thing called
that takes up a long time, which is why a dish like duck confi , you have to cook it
It's higher than those minor reactions, also. If you take a turkey leg and put it in water,
You'll come back a day later to an amazing turkey leg that's perfectly brined and everything.
can get things like lox or jerks or fish. It's like basically taking the salinity to
I don't know if you could actually like, cook a turkey in just salt. They have to be food
I'll get food poisoning.
go together. So, I had a friend come over at my house and looked at my not particularly
But when he asked like what, how do you know what goes with what, I had no answer for him
flavors will go together. And there's a great website called Food Pairings, where this guy
Somewhere in the book is a couple of screen shots from it, in Chapter Three, on page number--.
find it. Here we go, it should be that. Page 143. So, you'll see the top of that are two
smell things--. Well, sense of taste and smell are totally truly fascinating, 'cause like
So, some things taste sweet, some things bitter, sour, you know all these things. Maybe metallic
Smell is a lot more complicated. Your nose has somewhere in the order of ten thousand
current theory. And any given molecule can trigger a different number of receptors. So,
just like they would chord-wise in a symphony, go well together, will likewise go well together
families that strike the same receptors in your nose. And likewise, this is why it's
It's a dissonant. So, if you actually look at some of the more interesting combinations
it comes out of actual just experience. And a lot of top-end chefs will go and look at
>>FEMALE AUDIENCE MEMBER #12: All right. Does this mean I should go back and tell my friend
>>Jeff Potter: No. There are plenty of combinations. But using this, you would probably come up
>>FEMALE AUDIENCE MEMBER #12: So, A and B are good. B and C are good. C and A are good.
me at one point that I think you can bridge like--. You can't like jump four or five jump
to come up with a combination of three-wise pairs that don't work out chemically as a
if you could talk a little bit about safe defrosting, or does that not even matter if
a line if you've got frozen ground turkey. They say put it in your fridge overnight,
>>FEMALE AUDIENCE MEMBER #13: If you're trying to defrost fish over like, an hour time period
>>Jeff Potter: Water conducts heat a lot faster than air. So if you took that lump of frozen
40 degrees in your fridge and you put a third piece in your fridge, just in air.
vide in your oven if your oven went to those temperatures. It's just gonna take 23 times
keep in mind about the danger window it's like four hours. If you put it on your counter
fine. I mean, assuming you're starting with a fish that isn't slathered with salmonella
They're actually even frozen to kill parasites. 'Cause then you're not concerned about being
So, the issue is shellfish and various parasites. I mean, not that you usually leave fish on
[laughter]
There's one I don't want to talk about publically yet, so let's just say it involves some TV
>>MALE AUDIENCE MEMBER #15: I found it. A search for Jeff Potter high temperature pizza.
>>Jeff Potter: Pre-cached it?
I don't know if this is very useful. I will show you a photograph and then talk about
Pizza. It turns out you can make really, really good pizza if you're oven goes to about 900
a decade ago. He clipped the lock on his oven doors so he could open it when it's on the
home. Not that you should, but if you really want me to.
between like 800 degrees and 600 degrees. I put my hand in the oven at 600 degrees.
hand back. But the thing about doing pizza in an oven this hot, is that it cooks like
ever wondered how you get a really, really thin crust pizza, it's cooking it in a really
looking and put it in it. And it reads about a thousand degrees. So, the difference between
That's why you can't really do it at home. So here's the slide in question. One of these
which is quartz crystal. So the military used it on missile nose cones in the 1950s. Thank
plastic from the oven manufacturer.
It has to do with negative 320 degrees. I apologize that I did not bring my liquid nitrogen
just like heating pizza in 30 seconds. Basically, when you think about temperature--.
to your target temperature and beyond really, really fast.
that do freeze at this temperature range. So you can make ice cream that is literally
>>MALE AUDIENCE MEMBER #16: To what extent does the humidity of your oven matter?
>>Jeff Potter: Well, yeah. I mean, that's why bakers will oftentimes spritz or spray
It's something we just don't really deal with 'cause it's kinda hard to control for, at
>>FEMALE AUDIENCE MEMBER #17: [inaudible]
more moisture in the environment. It's gonna heat the outside of your food faster. So it
>>Jeff Potter: Aluminum foil.
especially if you're baking, like melted butter versus cold butter. If you use cold butter,
>>FEMALE AUDIENCE MEMBER #19: So then it melts out and that's why you can leave it in even
That's why chocolate chip cookies tend to flatten out really easily. But don't do it
>>Jeff Potter: Depends on what kind of cookies you like. So much variability. You think you
thousand different varieties of cookies because people like the variation.
>>Jeff Potter: Yeah.
You got a question?
>>MALE AUDIENCE MEMBER #20: You've done a lot of experimentation in the kitchen. Any
generic. What do I think you should have if you're gonna go and do experimentation in
temporary basis? If you're gonna go do experimentation in your kitchen, just like any science, anything
So really, understanding the temperature of the food, temperature of the environment,
we did an experiment where I had 500 people bake batches of cookies, each of them being
with whole wheat flour and one with regular flour.
basis that if one person is making both of these controls, there's gonna be variation
actually for a bunch of chemists down in New York. It's like a bunch of chemists given
had sheepishly come up to me and said, "I followed your protocol, but when I looked
about a three-page, bullet point, single spaced list that like, followed to the letter by
so much variation that when you're trying to do an experiment, really understanding
As for the second bit, the second question I said I'd answer, so I'm out in LA on a semi
I miss my immersion stick blender. And it's kind of funny 'cause I have a confession to
been fine. It's actually worked just--. I didn't miss not having an oven or burners,
There's so many things you can do with that one tool. I haven't been able to make soup,
that particular tool actually. It's hard to fake it with something else. You can't take
>>MALE AUDIENCE MEMBER #22: So, I guess my question is there's this other device that's
>>Jeff Potter: Microwaves are kind of underappreciated. I mean, they fundamentally work by vibrating
So you wanna steam some veggies, works great. Take a container. Put some veggies in there,
your asparagus or whatever your veggies are will cook.
You can make a cake in like 30 or 40 seconds. Again, because a microwave's retain water
That said, microwaves are not so useful for things that involve Maillard or caramelization
So, that's why microwaves don't get the love that maybe they deserved, because you can't
able to do some form of cooking in the microwave.
moisture that's present from the potato and get the starches to dissolve and set a. Do
intuitive, throw-everything-in-a-pan cooks can describe how to cook to the precise I-need-a-recipe
>>FEMALE AUDIENCE MEMBER #22: YouTube!
probably out of time, so with that, thanks for having me out.
[applause]