Sunday, October 4, 2009

LEAN TIMES: Kitchen advice column

I am sitting on a large quantity of oil which I don't want to go rancid. I expect to do a lot of baking this winter, so I was thinking of hydrogenating it. But I've heard that it's hard to do at home and not that good for the health?

Far from it. Don't be put off by what you read in the news about trans fats; when done right, hydrogenation can improve the quality and taste of oil and keep it in a waxy solid form that will last years, even when used daily for deep-frying.

Long a mainstay in the food industry, more and more consumers are choosing to harden their own fat at home, especially with the recession crimping food budgets. Although there are companies and labs that will hydrogenate fats for you, prices vary and you can't be sure that they specialize in culinary hydrogenation -- equipment being used now to hydrogenate a winter supply of oil may have been used for methanol in the spring or petrochemicals in the summer.

At the same time, many hobbyists have found that fat hardening can be a feasible and rewarding weekend project. Not only does DIY save money on by-the-gallon batch jobs, people who have a favorite flavoured oil they don't use every day might opt to harden it into an "heirloom margarine" for special occasions for generations to come.

To turn that messy, unwieldy oil into that beautiful, lustrous hard fat fit for the table or the next batch of melt-in-your-mouth (and only in your mouth) confection, you'll need to pass hydrogen through it at extremely high pressure. The two essential pieces of equipment are a hydrogen tank (here zeppelin hobbyist shops can be a good resource) and a piston compressor that is capable of compressing the gas to 30-40 bar. That may sound like a tall order, but if you live in a university town or larger city, you may be able to scrounge around the academic labs -- also keep your eyes peeled when a university advertises a new equipment procurement; sometimes piston compressors are disposed of.

Some contrarians like the New York Times' Mark Bittman say dihydronaphthalene or dihydroanthracene can be used just as well for hydrogenation, but most feel the pure bottled hydrogen gas gives the best flavour.

When Jamie Oliver "hydrogenates for his mates", he uses a Haug piston compressor with a nickel catalyst. Emeril -- who makes a "Cajun Crisco" from local artisan oils, prefers ruthenium and a much lower pressure. Whichever recipe you try, remember to play it safe. A mass spectrometer, if you have one in your kitchen, can be a good way to check to see if you have hydrogenated the right chemical bonds, and that the output is not toxic. Although it's inevitable that most of the catalysts and residues will end up in your first couple batches, don't be overly worried about these -- just be sure to use them only in lower-fat recipes. Most people find that their second or third batch is already quite successful.

As well as delicious.

3 comments:

Sharon said...

You know, I read a book on cider making that was eerily similar to this piece.

Only, you know, possible to replicate in your own communal village thingy. Should you have one.

It's actually one of my favourite non-fiction books. I picked it up to answer the question we all ask at some point ("How do people make cider, anyway?"), expecting to flick through it for the general gist, and ended up reading the whole thing.

I also ended up feeling strangely compelled to make cider out of the fall apples. Ah, if only I lived in a temperate climate and owned apple trees...

It was "Real Cidermaking on a Small Scale" by Michael Pooley and John Lomax, if anyone was interested. It seems to have disappeared from my library, and I can't be bothered buying it from overseas, so I guess I'll never find out if it's interesting to re-read, or if it was just a one-time fling...

Kristopher said...

We had 2 apples on our trees this year, in a year when Estonia is apple crazy. That's 2 (two) pieces of fruit! I think Giustino has his hands full with 22 trees, so he might be interested.

The backstory on this piece -- pure fantasy and not based on anything, except that trans fats are in the news. The story is that the Estonian First Lady complained in a local parent-teacher council about candy. Yep, it's sadly true -- Estonians are big about "food technology". I think it's an absurdity. Food should be the least industrial thing in our lives and utterly separate from labs. Hence this piece.

Kristopher said...

No, that's not entirely true what I just said -- have been reading John Seymour's very excellent Guide to Self-Sufficiency (available as an ipaper at scribd.com, ordered a copy as well). So you're probably pretty much dead-on in recognizing a certain style. Maybe the cider book is also online. It won't show up in Google but if you go to a site like scribd.com and search for it, you may find it or similar things.