Friday, November 16, 2012

Book review: The Art of Fermentation

Two words: Life. Changing.

Okay, no worries, I have more to say about this book than just two words.

The Art of Fermentation, by Sandor Katz, is a hefty book.  It's a large hardback and 500 pages long.  It discusses alcoholic beverages, fermented pickles, sour tonic beverages (like kombucha and kvass), yogurt and cheese, sourdough, Asian mold ferments (which include tempeh and sake), and even non-edible ferments like compost.  There are descriptions of fermentation techniques from around the world -- places Katz had actually traveled to sample the mauby or cassava or whatever.  And there are plenty of sketches and color photos, for those of us who (like me) can't always picture what an airlock or a block of tempeh looks like.

As an instruction manual, it's unmatched.  I've been making sauerkraut and other pickles for awhile based off of Nourishing Traditions, but I was frustrated because all I knew to do was to follow the recipes exactly.  If one ingredient was missing, or if I made a mistake, I was in trouble.  The Art of Fermentation isn't a bunch of recipes.  It tells you clearly what you have to have to ferment things, and how to know for sure it's working, and you can then turn around and ferment whatever you want.  So as I was reading, I kept thinking, "So that means I could ... well what if I ... I have to try ..."  It's like the difference from slavishly following recipes in the Joy of Cooking (my favorite cookbook) versus reading the "About the Ingredients" section and knowing you can make whatever you want for dinner, because you don't just know how to follow a recipe, you know how to cook.

Katz even includes troubleshooting for each type of ferment, so that I now know how to keep wine from turning into vinegar (keep an airlock on it) and what to do if my sauerkraut molds (skim it off, the rest will be fine).

I learned that fermentation is way easier than it sounds.  Some people ferment things, from yogurt to wine, by carefully sterilizing everything involved, inoculating with a purchased starter, and then hoping and praying they neither kill their starter nor catch some bad bug.  Katz's way is to learn what environment the microbe you want likes, and then give it that.  Yes, sometimes you need to add a starter, like when you're starting out with pasteurized milk or making one of the mold-based ferments.  But very often you don't have to!  You can make sauerkraut without adding whey like I've always done.

Maybe I've just been dumb all this time, but I seriously never knew you could make wine just by mushing up grapes and leaving them out.  There is yeast right on the grapes, so long as they are raw.  In fact, there should be sufficient yeast or bacteria on any raw ingredient you use: cider, fruit, honey, vegetables, or herbs.  As long as something in your brew is raw (and not irradiated either), you should be able to ferment it without a starter.  Purchased starters have disadvantages -- often they are not as strong as wild bacteria, and there are usually only a couple of species instead of a diverse batch.  If you're using purchased starters, you may find that they stop working after awhile.  This is because the single species in them has died of a virus or something.  Multiple species are less vulnerable.  If you need a starter and don't want to buy one, "backslopping" is the best way -- putting in a little of your last batch, or a batch of something else with similar bacteria.  (This is the method in Nourishing Traditions, where you use whey from yogurt as a starter for vegetables.)  Traditional cultures often did this by always using the same crock or pot for their ferments, without ever washing them.  The bacteria adhering to the pot were enough to get the mix going.

The real gem of the book, though, to me, is its philosophy.  Most of us have been raised all our lives to think "microbes = bad."  In reality, if you could completely sterilize yourself, inside and out, you would die.  Bacteria digest your food, create vitamins you need to survive, and are your first line of defense against infection.  Take Colostridum difficilis, the severe diarrhea-causing bacterium.  It's resistant to antibiotics.  So of course the main way you get an infection of it is to take antibiotics.  It kills off everything else in your GI tract, leaving nothing but C. difficilis there.  Naturally it overgrows all over the place.  Competition is vital to keeping bacteria in check.

The same thing is true inside a jar as inside your body.  Sterility is not a problem.  A flourishing ecosystem is not a problem.  But a monoculture of one very tough germ is very bad.  Take botulism.  Everyone is terrified of it, and in fact fear of botulism keeps people from making sauerkraut the old-fashioned way.  In fact, botulism is not a danger in lacto-fermented food.  Botulism is in the soil and you've probably eaten plenty in your life, on a raw veggie or your hands.  It's just one microbe, balanced by a whole ecosystem of microbes, and it can't compete.  But what if you heat a jar full of tomato sauce to 150 degrees?  All the bacteria will die.  But botulism has a special talent.  If you heat it, it forms spores which aren't destroyed until you get your jar much hotter than that.  (Official canning times are based on reaching an interior temperature that will kill botulism spores.)  You return your jar to room temperature and put it in the pantry.  The botulism spores hatch out and discover a wonderful world of food, all for them, with no competition!  They happily reproduce like crazy and produce lots and lots of botulism toxin, which you can't see or taste, but which will kill you when you dig into the sauce -- even if you heat it again before eating it.

But your lacto-fermented pickles?  They'll be fine.  Between the lactic acid produced by the bacteria and the salt added by you, it's a terrible environment for botulism, which won't survive.

Keep in mind, fermentation has been safely practiced by uneducated people for thousands upon thousands of years.  Sterilization (canning) has only been around for under 200 years.  It can be quite safe if done properly, but you have to heed the experts.  With fermentation, the main thing you have to heed is your own nose.  If the right bacteria are growing, you can smell a nice acid smell.  Yeast smells a little alcoholic.  Good bacteria smell appetizing.  If the whole batch tastes nasty or bitter (as happened to some yogurt of mine recently), the right bacteria didn't take hold and something else is growing there.  Odds are good it's something harmless, but you should throw it out all the same.

A really amazing thing about this book is the cool stuff I didn't know about microbes.  Like SCOBYs (symbiotic cultures of bacteria and yeast) such as kombucha, kefir, water kefir, and ginger beer plant.  They are large enough to be clearly visible as "grains" or "mushrooms" that you can put in liquids to ferment them.  They contain many different species of bacteria and yeast which complement one another and live off one another's byproducts.  The really cool part is that you can't create them in a lab.  You can't create them at all.  They coevolved that way, over millions of generations.  Milk kefir is the most amazing (to me) because obviously humans are the only animal that extracts milk and leaves it out for things to grow in.  In other words, we created the environment for a whole new kind of thing to evolve!  Do you realize how freaking COOL that is?

Sigh.  John didn't either.  I think it is awesome.  It's also awesome the way whole successions of bacteria grow in a culture, just like the successions of a forest.  One will grow that likes a neutral environment, and produces small amounts of acid.  When it creates enough acid, it dies back and gives way to a more acid-loving bacterium.  The ecosystem within your jar of pickled beets is changing all the time, and you can eat it whenever it suits you best.  You can take some rice, grow a mold on it which turns the starch into sugar, ferment that with yeast to turn it into alcohol, and then leave it for some acetobacter to turn into vinegar.  Transformation after transformation.

I think fermentation is an incredibly helpful thing to know if you want to be independent from reliance on electricity.  The power, as we've recently been reminded, can go out and then where will you be?  Wouldn't it be better if many of the things you needed to eat are already preserved?  Of course fermented foods also have health benefits.  Or rather, living without bacteria is detrimental to your health.  Western civilization is only one century into our war on microbes, and we're clearly coming out the losers.  We don't even understand a tenth of the interactions our bodies have with the microbes that live on and in them.

And of course, there's the taste.  What would the world be without bread, cheese, wine, kosher dills, or sausage?  Not a place I'd like to live.

I'll admit there were two places where I got a little skeeved out, despite my usual tolerance for microbes.  First off was the mold.  Tempeh and koji are both made with mold.  I just can't handle the idea of leaving beans in an incubator till they turn white and fuzzy and then eating it.  I know there's nothing special about mold compared with bacteria, but most things I've ever known that got moldy were really stinky.  It just brings me back to cleaning out the fridge when I was pregnant (which I wouldn't recommend to anyone, ugh).

The other was during the sausage making part.  I didn't realize sausage was fermented at all.  Katz says that a starter culture isn't necessary, provided you mix the sausage with your hands.  And it's okay to wash your hands first.  What that says to me is that even when you've washed your hands, there are still plenty of bacteria on them.  That is definitely not what I learned in school!  Of course you could use the triclosan soap that kills 99.9% of bacteria ... and hope and pray that the .1% they miss isn't something deadly.  Or just get used to the reality that your skin is teeming with bacteria.  Usually if the population of bacteria on your skin takes a hit, you suddenly get an overgrowth of yeast, and a red stinky rash in any moist areas.  You really do need them there.

Inspired by this book, I made a cranberry-apple drink.  I guess it's a country wine, because it's made with sugar water instead of juice, but I think it'll taste like cider.  It was crazy easy.  I chopped up an apple and some cranberries in the food processor and put them in a quart jar.  I added 3 cups of filtered water and half a cup of sugar.  (You can add a whole cup if you want more alcohol in the finished product.)  Then I put a cloth over the jar (to keep flies out while letting yeast in) and stirred it vigorously every time I passed by it.  For the first two days I saw barely any bubbles.  But the third day it woke up and started foaming like crazy.  Now it's fizzy and smells alcoholic.  When the fizz subsides a bit, I'm going to serve it up -- hopefully for Thanksgiving.  If I had an airlocked jug, I could let it ferment longer, but without one, I risk either making vinegar (if I leave it uncovered) or exploding my jar (if I put the lid on).  I'm sure it will be good as it is -- lightly alcoholic, lightly carbonated, and still sweet.  This is the way most beer and mead was served back in the day -- as "small" ale, only a little bit alcoholic.  Yeah, you know how they always told you that people in the Middle Ages never drank any water, only beer, because the water wasn't safe?  That's perfectly true.  But it wasn't strong at all.  The fermentation would help kill any harmful microorganisms in the water, and give a pleasant taste.

I strongly recommend this book.  It's great to get from the library, but for those of you who can't read 500 pages in two weeks, or would like to use it as a reference, it would probably be worth buying.  Especially if you buy from my link. ;)  One warning, though: it WILL make you want to start making your own kimchi, mead, kefir, poi, or natto.  If you read clear to the end, you will probably want to start a business selling fermented food.  This is the sort of book that could easily change people's lives.

I think I'd better go stir my country wine again, and taste the foam a little.  It might possibly be the best thing I've ever tasted.


momsomniac said...

My paternal grandmother used to make yogurt on top of the fridge (it was delicious) and she'd put fruit in a jar in the window a few months before Christmas and let it "get ready" for making the Christmans fruit cake. That fruit cake made is soooo giddy. And so...I never understood why people hated fruit cake! :)

Alison Jenne said...

Having my son throw up after eating my homemade kimchi, I'm not too interested in trying again.

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