Saturday, August 10, 2013

Notes on fermented foods

We're giving a class today on fermented foods. Since my printer refuses to function this morning, I'll post the notes here instead. Enjoy!


When microorganisms like bacteria, molds, and yeasts colonize and process various foods, it’s called fermentation. There are many different kinds of fermentation, just as there are many different kinds of foods and many different microorganisms. Some of these organisms are harmful, and will make food dangerous or unpalatable, but if it’s properly controlled, fermentation can create food that is nutritious, tasty, and long-lasting.

Many foods originated as ferments. Condiments, like ketchup, mustard, and chutney were once fermented, and eaten with particular foods because they would aid digestion. Few primitive cultures ever drank fresh milk, having no refrigeration to keep it fresh, but fermented yogurt and cheese have been common for centuries.

One of the most helpful types of fermentation is lacto-fermentation, which results from colonies of lactobacilli bacteria. These bacteria convert sugars and starches into lactic acid, which acts as a powerful preservative. Lactobacilli live all over the place, but are particularly common in raw milk, and are easily found in commercial yogurt. Many lacto-fermented foods store well without canning or freezing for several months; they also promote healthy digestion can help control infestations of Candida. Wild yeasts are also useful fermenters. They live in the air and all over normal household surfaces, and make foods like sourdough bread.

Fermented foods:
  • can often store better than the foods they’re made from
  • help fight disease
  • enhance and improve flavor
  • improve nutrient content of the food it’s made from, and improve absorption of nutrients from foods that accompany them
  • increase digestibility of their ingredients

The basic technique

To make fermented foods, you need something to ferment, and microorganisms to ferment it. Quality shows when fermenting, so start with the best quality ingredients available. For some kinds of ferments, you’ll also want a starter culture. You might strain yogurt to get whey for lacto-fermentation, or use things like sourdough starters, kombucha mothers, or kefir grains shared with friends. Cleanliness counts, so keep your containers and utensils clean. Chlorine-free water is also very helpful; water treatment systems chlorinate water specifically so that fermenting organisms can’t live in it. Many ferments require salt, to ward off unwanted bacteria while the fermentation gets going.

What foods can be fermented successfully?

Many vegetables ferment well. Foods with a higher sugar content are more likely to produce alcohol, so it’s harder to ferment fruits. Good candidates include cabbage, beets, carrots, turnips, green tomatoes, squash, onions, peppers, garlic, and cucumbers.

Tips for successful fermentation

  • Many home ferments require anaerobic conditions. In other words, keep oxygen out. Keep brined foods underneath the brine; close fermenting jars tightly.
  • Keep things clean.
  • When fermenting in jars, leave an inch of empty space at the top.
  • Metal reacts with ferments. Don’t ferment in metal containers, and avoid metal utensils.
  • Whey from yogurt or raw milk is often helpful to jump-start lacto-fermentation, especially with more sugary foods. It can replace some of the salt in lacto-fermented recipes.
  • Fermentation starts off very active, and then calms down. During the active phase, jars may hiss and release liquid. Put jars on a cookie sheet for the first week or so, to catch this liquid.
  • Fermentation goes faster in warmer temperatures.
  • Trust your eyes and nose when fermenting. Some food will spoil, and when it does, you’ll know it.
  • Many ferments require salt. The salty taste will diminish as the food ages.
  • When fermenting several foods simultaneously, separate them, to prevent the cultures from cross-contaminating.

Store foods with the lids closed, in cool, dark places. Basements often work well for this. High sugar content foods should be eaten fairly quickly; sauerkraut and peppers will last for years on a basement shelf.

Bad smells, stringy brine, and colored mold spots are bad signs, and indicate a ferment that should not be eaten. White mold (called “Kahm yeast”) isn’t harmful if it’s removed regularly.


What is sourdough?

Bread ferments with yeast, not lactobacilli. Different yeasts do different things. Commercial bread yeast acts very quickly, and as a result makes lots of alcohol, which cooks out during baking. Also because of its speed, commercial yeast cannot break down much of the less digestible parts of the flour. Wild yeasts, however, such as those used in sourdough bread, take longer to do their work. During this longer fermentation, new flavors develop, and the flour is broken down to be more easily digestible.

Bread makers who use sourdough generally keep a starter on hand to work with. This starter is simply a paste of flour and water, which has been allowed to ferment. With each batch of bread, the baker reserves some of the starter to use next time. These starters can last for centuries.

Caring for a starter

Keep your starter in a jar with a lid. You’ll need to feed your starter every day or so. Do this by mixing flour and water (ideally unchlorinated) in approximately equal proportions, and stirring it into your starter. A frequently used starter can be fed enough to double in volume, more or less, at each feeding, but starter used less often would grow unmanageably at this rate. Watch your starter to know if it is well fed. A healthy starter will smell OK, and produce lots of bubbles within a few hours of being fed.

Starters like to be moved to a new, clean container every few days, and don’t appreciate changes in the type of flour they get. Where possible, introduce new flours slowly. Starters must also be kept warm to remain active, so refrigerate it when you go on vacation, and keep it warm when you want it to work quickly.

A starter that has been neglected on the shelf can smell fairly bad, and sometimes become slimy. These can often be resurrected by scraping off the top layer and carefully removing some of the still-viable starter underneath. Mix this into some new flour and water, and discard the rest. Starters left in the refrigerator often develop a layer of black liquid, which is perfectly safe. You should simply stir it back into the starter when you’re ready to use it again. A small layer of white mold on the starter can be scraped off or just stirred in, but black or colored molds are a bad sign.

Making a new starter

Old starters with a long pedigree are neat, but starters made fresh with yeasts local to their area often perform better. To make a new starter,mix a few tablespoons of flour and water into a dough or thick paste. Leave this paste in a bowl or jar, covered loosely to keep insects out, for a day or two. It should begin to develop bubbles. Feed it normally for a few days, keeping it loosely covered. Within a week it should develop bubbles. If it does, you’ve succeeded. Transfer it to a jar with a lid, and use it as you would any starter. If it doesn’t, throw it out and start over.


ALWAYS set aside some starter before using the rest in a recipe.

Pancakes and waffles are more forgiving to a misbehaving starter than bread is. If your starter smells funny or isn’t as active as you’d like, make a few batches of pancakes or waffles from it before trying to make bread again. This is a good way to develop a newborn starter into something useful.

Whole grain flours go rancid after grinding. It helps to grind your flour fresh each time you use it, but you can also keep fresh flour in the freezer for later use.

Some grain grinders heat the flour quite a bit, so the starter won’t take to it well. This is the sign of a lousy grinder.


Ginger Carrots

4 C grated carrots
1 T freshly grated ginger
1 T sea salt
4 T whey (or another Tbl. salt)

Mix all ingredients, and pound them with a meat hammer or wooden pounder, to get some of the juices out. Pack tightly into a quart jar, leaving an inch of head space. Add water if necessary to cover the carrots. Close jar tightly, and leave at room temperature for three days to ferment. Transfer to cold storage.

Pickled Beets

12 medium beets
1 C water
1 T sea salt
4 T whey (or another Tbl. salt)
2 tsp. cardamom pods (optional)

Peel and dice beets (grated beets will ferment too quickly). Place them in a quart jar and press lightly with wooden spoon or pounder. Combine remaining ingredients and pour over beets, adding water as needed to cover them well. Leave one inch of headspace in the jar. Close jar tightly, and allow to ferment at room temperature for about 3 days before moving to cold storage. The beets are tasty; the liquid (called beet kvass) isn’t so much, but is very healthful, even diluted quite a bit.

Pickled Peppers

10-25 various peppers, hot or otherwise
3 T sea salt
1 C water
spices as desired; cumin is especially good

Cut peppers into pieces. Press firmly into a quart jar. Combine other ingredients and pour over the peppers, adding more water as needed to cover them. Leave an inch of headspace. Close jar tightly, and ferment for a week or so at room temperature before moving to cold storage. Keeps for years.

You can substitute whey for some of the salt, if you wish. The result will be more sour, and probably less crunchy.


Firm cabbage
1 T sea salt per head of cabbage
Spices as desired. Some suggest juniper berries, which taste lousy but may help the cabbage remain more crisp

Slice or grate cabbage, and add salt. In a bowl or bucket, pound the daylights out of the stuff until the juices come out. Add spices, and pack very tightly into jars. Add water to the jar as needed to cover the cabbage, leaving an inch of headspace. Close jars tightly, and leave to ferment for a few days before moving to cold storage. You can substitute some whey for the salt, if you wish.

Water kefir

2 quarts water
½ C sugar
about 2 T water kefir buds

Some sources insist white sugar is required for water kefir, while refusing to countenance refined sugar in other recipes. Other sources use sucanat and other unrefined sugars without a second thought. The molasses in unrefined sugar will change the taste, and color the otherwise transparent kefir buds. Experiment with both, if you like. Also, please note that kefir buds don't respond well to the oils from skin, so don't touch them. To make water kefir, mix water and sugar in a jar. Add kefir buds, and cover with cheesecloth. Keep in a dark place for three days. Then strain out the buds for a new batch. We add a bit of juice to the kefir for flavor. If after filtering out the buds you add a little more sugar and allow to ferment another day with a tightly closed lid, this will become more carbonated.


1 gallon freshly brewed tea, at room temperature
1 C sugar
kombucha mother
½ C kombucha from a previous batch, or white vinegar

The same notes on sugar that apply to water kefir apply to kombucha as well. Black tea is traditional, but green tea and herbal teas will also work, even if they raise the ire of kombucha purists. The caffeine and other harmful substances in black tea are largely consumed and transformed by the fermentation process. To make kombucha, mix tea, sugar, and kombucha or vinegar in a jar or bowl. Add mother, and cover with cheesecloth. Allow to ferment 7-10 days. Then remove the mother and enough kombucha for the next batch. Many people dilute the result somewhat with juice. As with water kefir, you can ferment this a second time with a tight lid to make it fizzy. You may find strings of premature mother in the result. You can drink these, or pull them out. With the proper environment these may even make a new mother for you. Note that your mother will grow as you brew successive batches. You'll see the mother will have several layers, one for each batch. Many people choose to remove older layers on occasion, to keep the size of their mother down somewhat. You can touch kombucha mother with clean hands, without danger of hurting it.

Sourdough pancakes or waffles

Feed starter in the evening sufficiently to make three or four cups of doughy starter, and leave covered in a warm place overnight. In the morning, set aside a bit of starter for future use, and to the rest add a pinch of salt, two beaten eggs, a teaspoon of baking soda, and water or milk as necessary to make the consistency of batter. Cook normally.

Sourdough bread

A cup or three of sourdough starter
Several cups fresh flour
1 T salt, per loaf of bread

This recipe is fairly inexact, consistent with our baking practices. Set aside some starter for the next use. Dissolve the salt in a cup or so of water, in a large mixing bowl, and add the remaining starter. Stir well. Add flour or water as needed until there’s as much dough as you want, and it’s a good consistency; we find enough semi-sticky dough to fill our stoneware bread pan works well for us. This dough is too sticky for kneading, so here we just dump it in the pan, cover it loosely, and let it sit for a few hours. Timing here is also a matter of taste. Left longer, the sour flavor will increase, and the bubbles will be bigger.

For a time we would make stiffer dough than we do now. Back then we found that leaving it to sit for 10 minutes did wonders for its consistency. With the stiffer dough we would let it rise in the covered mixing bowl for a while, before putting it in the pans and allowing it to rise, covered, a second time. Most people advise against using metal with sourdough, and presumably this extends to metal loaf pans, but we never had a problem with ours that we attributed to the pan.

Once in a pan and allowed to rise, the dough is ready for baking, at 350F. Our pan takes an hour or so, but we end up taking the bread’s temperature with a meat thermometer. It should get to 165F.