Tofu - at what temperature does it cook?

December 29, 2005 6:44 AM

Tofu - at what temperature does it cook?

I eat a lot of tofu. I've started cooking a lot of tofu. It seems to disagree with me if it's not fully cooked. But how much cooking is enough to avoid this unfortunate effect? Is boiling sufficient/necessary? I'm interested in using a meat thermometer to figure out how much heat I need to apply, so I can innovate successfully.

I did some googling but couldn't find the answer. I also found a thread here on tofu cooking (asking about getting the center unwatery) and followed links from that thread, but no joy.

posted by amtho to science & nature (16 comments total)

"Raw" tofu is already cooked. A gassy or ill-feeling response to eating unheated tofu is probably due to bacteria. If you want raw-like tofu, that page suggests a 5-10 minute steam and then putting it in the freezer to quick-chill it.
posted by Plutor at 6:54 AM on December 29, 2005

How are you cooking it when it disagrees with you? Steaming, boiling, frying?

(I press my tofu under a cutting board with heavy cans on top to keep it from being watery.)
posted by bcwinters at 6:58 AM on December 29, 2005

The problem is usually when I've gotten it in a restaurant, maybe on a salad or in a dish that didn't seem quite done. I don't think I've ever swallowed it raw at home; I usually cook the heck out of it.

I know, horrendously unscientific. I'm looking for other people's science.

Anyway, the texture (and flavor?) do seem different/better when the tofu is cooked.

When you say "Raw" tofu is already cooked, do you mean that part of the process of making tofu includes heating? Or do you mean the "cooking" that comes from the un-heated tofu-making (curding) process?

I do have a pretty sensitive stomach, so even if other people can eat raw tofu, that's not going to convince me.

Thanks for the article; useful information no doubt. Even if bacteria is the problem, I'd be interested in finding the exact temperature needed to destroy the bacteria.

But I'm also looking for the exact temperature to "denature" (?) the soybean protein.
posted by amtho at 7:17 AM on December 29, 2005

isn't the difference between marinating meat and tofu that the protein doesn't need to be denatured in tofu, and so you only need to marinate for a little while?

this page tells me that soy proteins are denatured at the boiling point.
posted by soma lkzx at 7:52 AM on December 29, 2005

here's what i was thinking of:

"Of course, the word 'marinade' and the word 'brine' share the same etymological roots, but there is a big difference in practice. You see, a brine really just refers to a salty liquid. But a marinade always includes acid, either citrus juice or vinegar, wine, something like that in order to tenderize the proteins of tough cuts of meat. But here's the thing, tofu's proteins are already coagulated, i.e. cooked. So, tenderizing is not really an issue. However, flavor injection is."

from every mefier's most trusted food source, alton brown
posted by soma lkzx at 7:54 AM on December 29, 2005 [1 favorite]

It's already cooked. Your indigestion is either your imagination, due to another food, or a general intolerance to tofu.
posted by rxrfrx at 8:12 AM on December 29, 2005

I just have to mention, have you ever had fresh tofu? It is the most amazing experience ever. None of the beany taste, and being fresh I'm sure it does not have the amount of bacteria that tofu sitting in water for weeks is growing. Fresh tofu is like the most divine of custards, more delicate and comforting. (If anyone is in NYC there are plenty of places to get it, En Japanese Brasserie, and the HOT TAHO take out place south of Bayard on Mott.)

And yes, tofu is made by boiling the soy milk that has come from the soybeans. Fresh tofu is warm. Thus packaged tofu is a product that was originally warm and thus the perfect environment for bacteria.

While I don't have a method for eliminating the bacteria, if you're into tofu, I recommend fresh tofu.
posted by scazza at 8:29 AM on December 29, 2005

You might try fully freezing and then thawing your tofu before you eat it. We do this when making dishes where the tofu stands in for real meat. Freezing changes the texture significantly, making it more fibrous and chewy rather than smooshy. It seems drier as well.

I have nothing to offer regarding your indigestion, however.
posted by putzface_dickman at 8:47 AM on December 29, 2005

Of course, the word 'marinade' and the word 'brine' share the same etymological roots

No they don't. Marinade is (via Italian) from Latin mare 'sea'; brine is from Old English brýne, bríne, of unknown origin.

On topic, I second scazza's recommendation of fresh tofu.
posted by languagehat at 9:58 AM on December 29, 2005

Wildly off-topic, but I think what the esteemed Mr. Brown might have meant is that both mare and brine both refer to the salty sea, although, as you say, their origins are quite distant save perhaps some (unlikely) proto Indo-European connection.

Anyway, it seems to me that if tofu is already cooked, then what you're interested in is killing any bacteria that may have gotten onto either the tofu or whatever else you're cooking it with. In that case, boiling is always sufficient, but (to take a page from meats), anything that gets the internal temperature above 180 degrees should kill just about everything. Cf. USDA food safety information, which is pretty conservative with their numbers. You could probably get away with less, but clearly you're interested in playing it safe, which is reasonable.
posted by jedicus at 12:39 PM on December 29, 2005

Yep, bean curd is cooked during the creation process. Subjecting it to high heat will change it's texture. Freezing will dramatically change the texture (it gets "fluffy" and will soak up sauces/flavour) - some people like it, some people don't. As for bacteria... I'm skeptical that that is causing the problem.

Second fresh tofu - also, there are many, many, many different kinds of tofu, not just the quivering white bricks that supermarkets carry.
posted by PurplePorpoise at 12:40 PM on December 29, 2005

anyone have any good recipes for creating my own fresh tofu?
posted by any major dude at 1:57 PM on December 29, 2005

any major dude I don't have an exact recipe, but basically it's strained soymilk (boil ~2 cups ground soybean [fresh or soaked overnight]: ~3 cups water for 20-30 minutes) with plaster of paris (calcium sulphate?) added to it (the more, the firmer).

I've seen it done in small batches and it doesn't turn out nearly as well as huge industrial batches. In really large patches, a film rises to the top - this is taken off carefully and can be used fresh as a desert ingredient, followed by a couple more layers of film (which are skimmed, dried; iirc the 2nd skim is used for stews, and the 3rd is typically used for soups. The remaining tofu will be of different grades (the topmost to the bottommost of the container).

Alternative tofus can be made by adding less plaster and more sugar (for sweetened dessert tofu) or more plaster (for firmer tofu which can be seasoned and dried). Firmer tofu can be fried, as can less-dense and "gassy" (think swiss cheese) kinds which are typically cut in half and stuffed with meat. Also, medium-firm tofu can be fermented and deep-fried for "stinky" tofu; it stinks like heck but it's oh so good.

I see you live in NY; I'm sure there are local tofu concerns which may offer you high quality fresh and varied tofu/beancurd... There's one in Vancouver's Chinatown that's great; it's basically a factory in a commercial footprint - they make and sell many different kinds of fresh tofu.

/fond memories of buying plastic pails of sweetened dessert tofu and eating it with light golden syrup
posted by PurplePorpoise at 3:37 PM on December 29, 2005

Thanks! Very interesting. I wonder if I occasionally get tofu from a batch that isn't fully cooked, though. This thread is past, but if I could ask again, I'd wonder if the soy milk _must_ be cooked before it will coagulate. What if it's only partially cooked?
posted by amtho at 7:17 PM on December 29, 2005

Soy milk, the precursor of tofu, is prepared by cooking/boiling ground soybeans. No boiling, no soymilk.

(I suppose there may be other industrial means of creating soymilk, but traditionally, the soy beans must be cooked to yield soymilk.)
posted by PurplePorpoise at 8:16 AM on December 30, 2005

any major dude - A "Recipe" for tofu (I found this accidentally looking at what magnesium sulphate (epsom salts) can be used for, kid's chemistry experiment-wise).

Scroll down to section 3.
posted by PurplePorpoise at 12:43 PM on December 30, 2005