Fermentation is pretty magical, but it’s also a predictable and logical process. As I’ve been writing Getting Started pieces for the blog, it occurred to me that I should write up a piece on the real basics of vegetable fermentation, which I’m calling “The Three S’s,” – salt, submerge, and sit.
Why? Salt does several things in your ferment, whether you’re dry-salting something like cabbage or adding a brine you’ve mixed to cover things like carrots or cucumbers. For dry-salted vegetables, it helps draw out liquid from the vegetable, creating a liquid barrier over the top that keeps out molds and other unwanted organisms. Salt also creates an environment uniquely suited to the beneficial organisms that ferment foods, and that is inhospitable to pathogenic organisms that we obviously don’t want to culture in our food.
What kind? Any salt will do, but every resource I’ve seen says to avoid iodized salt. Iodine is a disinfectant, so that makes sense. I use Pink Himalayan Salt, which is readily available at Costco, but any non-iodized salt will do.
How much? While most people want a clear rule, the fact is that precise amounts aren’t all that important. Europeans seem to prefer less-salty ferments, with about 1% salt concentration, while American recipes typically start at 2% and go up from there. “Salt to taste” is a fine rule to go by. If your brine tastes too salty for your palate, dilute it until you can stand it. There really aren’t hard and fast rules.
What do you mean, 1% and 2% salt? For fermenting nerds, a digital kitchen scale that displays grams (aff) can be a useful tool for calculating fairly precise brine percentages. If you’re mixing a brine, for every liter of water (1000mL), 10 grams of salt is 1%. A quart is a little less than a liter, but if you want a given percentage, using grams to quarts is close enough for government work. 20 grams of salt in a quart puts you in the 2% range, 30 grams in the 3% range, and so on.
But look – a tablespoon of salt per quart will be fine most of the time. A tablespoon of salt per head of cabbage will produce sauerkraut. So will two tablespoons. You don’t need fancy equipment or precise measurements, you just need to salt, submerge, and let your ferment sit.
Why? The layer of brine that your fermenting vegetables soak in is your best defense against unwanted organisms growing on your vegetables. Solids that are floating, and being exposed to oxygen, can be an entryway for yeasts and molds that we’re not trying to culture. Whether you’ve dry-salted or poured brine in, you’ll want to keep an eye on your veg to make sure that they are well-covered by the brine.
How? Weight systems are as varied as fermenters. If you’re using an open crock, putting a plate over the vegetables and a gallon jug filled with water will keep your vegetables submerged. If you’re working in Mason jars, putting solid vegetables like onions, celery, or carrots under the shoulders of the jar can be an effective barrier to keep everything submerged. Just make sure those vegetables are submerged, as well. You can use the “jar-in-jar” method, where a smaller jar is pressed into the fermentation vessel and used to weight everything down. I’ve seen people who’ve cut bamboo skewers to press on the surface. A number of glass fermentation weights exist as well. As you probably know, I’m a big fan of Pickle Pebbles (aff) because I can drop one in and then put the standard lid on the jar. It’s a neater appearance, but obviously it’s a solution that costs money.
If you aren’t using the lid that came with your jar (and many weighting approaches make that difficult or impossible), make sure you cover your jar with a towel, coffee filter, or other tight-weave cover (not cheesecloth, which fruit flies can get through). Here are some examples of submersion techniques:
Why? This is where the element of time comes in. Letting your ferment sit, more or less undisturbed, is the last element in creating an environment where beneficial fermentation microbes can do their work – unlocking nutrients, breaking down indigestible components of the vegetables, and imbuing the vegetables with the unmistakable tangy flavor of fermentation.
How long? This varies. As I’ve discussed elsewhere on the blog, I often make sauerkraut in batches of five or six quarts at a time, getting into the first one as soon as a week in, while the rest sit out to continue fermenting. By the time the last jar is opened, it’s extremely sour, and I’ve had the pleasure of experiencing a long spectrum of flavor profiles. People whose primary interest is in eating microbes can rest assured – there are active organisms present at every phase of even a long fermentation, and no consensus about what organisms we should be consuming. If you’re interested in eating bugs, I suspect my approach is the way to go, though for me it’s a lazy adaptation to not making kraut often enough.
But don’t I need to….? Yes, there are a few caveats to the “let it sit undisturbed” idea. As I mentioned in the last link, I open my Mason jars up frequently to scoop out floating vegetable bits, spices, and clear off any foam. Many people like to solidly close the lid on a jar, which means they have to “burp” the jar once or twice a day for a week or more. If you’re using something like a Harsch crock (aff) with a water seal, you’ll want to check the moat and make sure the water hasn’t evaporated out. If you’re using a standard crock with no lid, it may be beneficial to uncover it every few days and run a strainer over the surface to submerge mold spores before they can bloom.
In Mason jars, you need to watch to make sure that you have adequate brine. Mine usually hit a point at a few weeks in where the vegetables suddenly reabsorb much of the liquid they bled out at the start, and if I’m not careful, I can end up with (acidified, preserved) cabbage sitting unprotected by brine. It’s usually not catastrophic for all those parenthetical reasons, but it’s not ideal. Topping off with brine or moving the batch to the fridge is the right way to proceed at this point.
The Three S’s
So that’s what I have to offer as the critical components for fermentation – Salt, Submerge, and let your ferment Sit. As you can see, there’s a little more to it at every step – or not! We’ve all evolved our own methods and procedures. What’s the most important step in your fermentation process?