Tuesday, February 23, 2016

Fermentation and Salt

 "Fermentation by definition is an anaerobic process. The lactic acid bacteria that carry out dairy and vegetable fermentations can grow in the presence of air but do not use oxygen to generate energy for growth. Using a fermentation lock to exclude oxygen but allow gas to escape will prevent aerobic yeasts and molds from growing. Aerobic yeasts and molds growing on the surface of sauerkraut brines can soften the kraut and produce off flavors. A more serious problem is that yeasts and molds growing aerobically on the surface of vegetable fermentation brines can consume the lactic acid and can cause pH to rise above 4.6, potentially resulting in botulism. Anaerobic fermentation of cabbage, on the other hand, with 2% salt (NaCl) and a temperature around 18C (64F) typically makes very good quality sauerkraut".  Dr. Fred Breidt, USDA, Microbiologist

Weight Matters
Salt is to brine, like flour is to a well-made bread.  Proportions matter, and in both cases, measuring spoons and cups are inadequate tools when it comes to obtaining the correct amount of dry ingredients.  Just like every type of grain has a different weight, every salt has a different weight depending on its grind, density and moisture content.  Salt, like flour, is a more reliable, consistent ingredient, when weighed - NOT measured.

To illustrate...Each dish in the above-photo contains 1 level-tablespoon of unrefined, additive-free (no added iodine or anti-caking agents) high-mineral salt, every one a unique brand and grind, ranging from super-fine to large and coarse. Several are moist, some are bone-dry. The brick-red Hawaiian salt (NOT meant to be used as a brine-salt, but instead, a "finishing" salt) contains added clay.  Using a digital scale, set to metric-grams instead U.S. ounces, we weighed each tablespoon of salt.

The end result:  Their weights ranged from 10 to 16-grams per tablespoon. That's a whopping 60% difference, negatively or positively impacting salinity!  Variations in salinity will impact fermentation.  

Salt helps lactic acid bacteria win the microbial race.  At a certain salt concentration, lactic acid bacteria grow more quickly than other microbes, and have a competitive advantage.

Below the correct concentration, bad bacteria may survive and spread more easily, possibly out-competing lactic acid bacteria and spoiling your pickles. Also, lactic acid bacteria don't survive in brines that are less than 1%.  The "no-salt" fermentation movement doesn't have its roots in traditional fermentation, but instead, in modern misunderstandings about the importance of salt.
Too much salt is also a problem.  Lactic acid bacteria cannot thrive, leaving your vegetables unpickled, and instead, salt-cured.  Salt-cured has always been a traditional method of fermentation, but it is intentional - meant to kill lactic acid bacteria.  What's more, salt-tolerant yeasts can spread more quickly.  By consuming lactic acid, yeasts make the pickles less acidic - and more hospitable to spoilage microbes.

Weigh, Don't Measure Salt

1. Use easy-to-read brine-tables - based on traditional formulas used by artisan butchers, cheese and pickle-makers.
2. Create the amount of brine you need, whether 1-cup, 1-gallon, or 1-liter, at the proper salinity-level, following our easy-to-read chart.
3.  Buy a gram-scale.  Digital scales are inexpensive - under $20 - readily available.  Make sure there's a "tare" button to zero-out your scale, to obtain the most accurate weight. Scales have a toggle-switch on the underside, one-side labeled "OZ", and the other, "GM". Switch the switch to GM - grams.

Which salt is best?

We recommend most dry salts - never wet.  Wet salts typically contain clay or dirt, providing coloration (grey, red, brown, etc.) but they also act as a "substrate", a surface on which mold grows.  Even when wet salts are baked at a very high temperature, in the hopes of killing mold, rsearch has shown that many mold spores survive.   Another issue, not talked about enough, is the lead-content of many northern salts.  All salts are graded, like a good wine, according to their quality and  use.  We prefer a gourmet-grade for any culinary use, including fermentation.  

2%?  3.5%? 5%? 10%? Which brine is best?

Dr. Fred Breidt, a USDA microbiologist and UNC microbiology professor is quoted in mainstream pro-fermentation articles, as saying that properly-made "lactic acid fermentation is SAFER than canned food".   Dr. Breidt enthusiastically suggested that we could reduce the amount of salt normally used in other methods.  Because our anaerobic-container suffocates oxygen-rich mold and yeast, the excess salt is NOT inhibit their growth.  "Anaerobic fermentation of cabbage, on the other hand, with 2% salt (NaCl) and a temperature around 18C (64F) typically makes very good quality sauerkraut."
Dr. Breidt's summary was: "Using the 2% with its anaerobic-conditions, would create a consistently good end-product with superior results in taste, flavor and color retention."

2% Salinity:  Carrot sticks, shreds, slices; broccoli, cauliflower, pearl onions, green beans (add grape leaves to preserve color), asparagus, green/red peppers de-seeded, parsnip, kohlrabi, Jerusalem artichoke, zucchini (whole), sliced radish, whole-small radish, whole green tomato, are but a few examples. Quick guide: Fill the Pickl-It with food (dice, chunk, whole, etc.) to 1-inch below the "shoulder".  Add 2% brine to the "shoulder" so your vegetables are covered with 1-inch of brine.
3.5% Salinity: Pickled cukes for pickling-varieties such as Kirby or Boston.  Fermented short-term (7-days on-counter, then 2 weeks in fridge) creates "half-sour" - still half-white, somewhat green inside.  More fermentation-time creates evenly-distributed green color and sublime flavor.

10% Salinity:  For those serious about brine-curing meat, crafting authentic feta-cheese, pepper-mashes, curing green olives, authentic fish-sauce, and shrimp-sauce.

Chart #1:  Water is U.S. Measurement, salt in grams.

Examples: To create 8-cups of brine at 2% salinity, use 38 grams of salt.  To create 3-cups of brine at a 2% salinity, add the amount of salt called for in the columns under 1-cup (5 grams) and 2-cups (10 grams) which equals 15-grams of salt. If creating a 1% brine, simply divide the 2% salt grams by 50%.  To make a 1% brine for 2-cups of water, use half of the 5-grams, ROUND DOWN to 2 grams.  


Adapted from http://www.pickl-it.com

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