About 50% tear gas should do.
March 4, 2010 2:16 AM   Subscribe

How do I get the hot kind of mustard oil?

A while ago, I ate delicious jiaozi at a restaurant in Beijing. They also had a tiny bottle of stuff that was like more potent liquid wasabi and improved the experience a lot when added to the vinegar/soy/etc mix in drops. I was told that it was "mustard oil", and so I set out to buy some for myself back in Europe.

After being dissuaded by the "for external use only" labels first, I ended up buying a bottle of boring mustard oil and found out about the two kinds of mustard oil. I want the hot one, but the people I asked at Chinese stores do not know what I'm talking about and try to sell me other types of cooking oil.

Will I be able to buy this outside a chemistry store? Make my own? How clever is it to mess with this given Wikipedia's affectionate description of allyl isothiocyanate as "fairly toxic and a dangerous lachrymator"?
posted by themel to Food & Drink (13 answers total)
Lachrymator just means a substance that makes you cry. See the word lachrymose.
posted by dfriedman at 2:32 AM on March 4, 2010

Dunno where you're living now, but Indian grocers will be able to help you out. Tread very carefully indeed; that stuff is liquid napalm and will turn your colon into Vesuvius and your toilet bowl to Pompeii, except it won't be ash that it's smothered in.
posted by smoke at 3:33 AM on March 4, 2010 [3 favorites]

If I recall correctly, long term consumption of mustard oil is linked to heart problems, hence the "for external use only" on the stuff in Indian grocery stores.
posted by electroboy at 5:49 AM on March 4, 2010

Also, yow!
Mustard oil is also used for rub-downs and massages (see ayurveda), thought to improve blood circulation, muscular development and skin texture; the oil is also antibacterial. The oil is also sometimes used prior to sexual intercourse on the male genitalia to enhance erections or strengthen virility.
posted by electroboy at 5:54 AM on March 4, 2010

Yeah, I think the stuff from the Indian grocery is what you want. The "external use only" label is just to get around the law -- everybody who buys it uses it for cooking. The issue is erucic acid, which is supposedly toxic, but only in huge amounts. You'd have to drink a bottle of the stuff every day to match the quantities used in the studies. Like it says the Wiki article, in Indian cooking, it's heated to the smoking point before being used, which reduces its pungency and supposedly the erucic acid content. But a few drops, unheated, on some dumplings almost certainly won't do you any harm.
posted by neroli at 6:33 AM on March 4, 2010 [1 favorite]

We use mustard oil in our lab. Be careful when you're using it -- ours has more allyl isothiocyanate than the Indian-grocery kind probably does, but we have to use ours in a fume hood because otherwise we tear-gas ourselves. As neroli says, it should be OK to eat in small quantities, but some scientists use it as a model of irritable bowel syndrome (i.e. you probably don't want to gorge on it, because your colon will be made really unhappy).

Also, I suspect that it loses potency/pungency really fast, because we need to keep ours stored in the refrigerator under nitrogen for long-term storage -- we think it reacts with the oxygen in the air, and if we don't store it under nitrogen, our cell cultures don't respond to it. So I wouldn't plan on having it be good for more than a month, at the outside.
posted by kataclysm at 7:12 AM on March 4, 2010

allyl isothiocyanate is, to use technical language, fucking nasty stuff (also, a suspected carcinogenic, mutagenic, theratogenic substance). Usually food grade mustard oil is at least 1:500, and still more than enough to give you a pretty bad eyeburn.
One of the names for the stuff is "redskin", make of that what you will.
posted by _dario at 7:13 AM on March 4, 2010

I wouldn't worry too much about the carcinogenic/mutagenic/teratogenic properties of allyl isothiocyanate -- after all, most of those studies are done with really high doses of whatever chemical they're studying. EVERYTHING is toxic if you administer too much of it, even water.

Plus, food tends to have small quantities of carcinogens anyway (like the acrylamide in fried foods, the nitrosamines and heterocyclic amines and PCA's that form when you grill meat, the benzene in your eggs and veggies, the nitrites in your bacon, carcinogens that are byproducts of fermentation chilling out in your beer and yogurt, etc.) If you didn't eat anything that had a carcinogenic molecule in it, you would probably die of either boredom or malnutrition. Hell, small amounts of some carcinogens are actually beneficial.

Really, you're going to get more cancer from UV exposure or breathing exhaust fumes in the city than you'll get from eating some mustard oil now and again. And everything's gotta kill you sometime.
posted by kataclysm at 7:44 AM on March 4, 2010

If you're adding it to a dipping sauce anyway, you might try Chinese or Korean style mustard powder. It's made from the same sort of mustard seeds, and imparts some serious heat, but without the ZOMG BIOHAZARD warning labels and the storage difficulties that others are reporting for the hard stuff.

There's actually some pretty interesting science here. The mustard powder as it's sold does not contain any allyl isothiocyanate. Rather, it contains two other naturally occurring chemicals which react in the presence of water to form allyl isothiocyanate. If you add a few pinches of mustard powder to a water-based condiment, you are basically brewing your own hot mustard oil by allowing this reaction to occur. In dry form, the powder lasts forever, is totally safe to handle, and so on. And when you add it to water, the mixture that results is very, very dilute, so again you don't have to worry about getting a little bit on your hands or catching a whiff of the fumes. I wouldn't rub it in your eyes or roll around in it, but you knew that.

What you do need to look out for, from a culinary point of view, is temperature. As others have pointed out, allyl isothiocyanate is unstable — and it breaks down faster the warmer it is. If you add the mustard powder to cold water, you get the wasabi-like zing you're looking for. If you add it to hot water, you get a mild, Dijon-y flavor. If you boil it for a while, you get all the pungency and flavor of bright yellow stadium mustard.

Even mixed with cold water, the stuff will lose pungency again over a few hours or a day. (It will last longer in your fridge, and even longer in your freezer, and in theory at a low enough temperature it would last FOREVER.) So the recipe goes like this: shake some mustard powder into your cold dipping sauce, let it sit ten or fifteen minutes while the reaction that produces allyl isothiocyanate takes place, and then eat it while it's at its peak.
posted by nebulawindphone at 7:57 AM on March 4, 2010 [4 favorites]

Response by poster: Thanks everyone, and sorry for the late reply, I wanted to wait until I could report back from grocery hunting.

Another round of two Indian and one Chinese grocer brought more shrugs. All of the have the cooking oil, but have never heard of the hot one.

@nebulawindphone: The only mustard powder available in all these groceries is household Coleman's, and that doesn't even match ordinary Wasabi. However, I'll need to do some more research on this one, since this, at least, seems to exist on the Internets. Thanks for opening a new line of inquiry!

The sad thing is that I can't even seem to find any references to culinary uses of hot mustard oil on the internets.

Oh, and thanks for all the science stories, next time I get drunk around chemistry grad students, I know just what to do.
posted by themel at 10:47 AM on March 6, 2010

AFAIK, the difference is that the Chinese-style powder is made from brown mustard seeds, not yellow.
posted by nebulawindphone at 7:50 PM on March 7, 2010

You, my friend, should try Penzey's Spices. I'm lucky enough to have a store in my city, but you can order their spices on the Internet too. Really high-quality, reasonably priced, and they have Chinese-style mustard powder.
posted by kataclysm at 8:14 AM on March 8, 2010

Response by poster: @kataclysm: Thanks, but I'm on another continent, so I'll shop around "locally" a bit more before going that route.

Another day's searching found me this forum thread, which was very helpful. Apparently, what I'm looking for is actually Korean and called "hot dressing oil", which tantalizes me with two vendors in the Google results. One is down, the other inscrutable.

Looking for Korean mustard oil also got me an some info about its alleged uses in North Korean and Chinese torture techniques, ew. Nevertheless, I feel that we're getting somewhere.
posted by themel at 1:10 PM on March 9, 2010

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