By Countertalk staff member and fermentation teacher Jeanne Kessira.

After a seemingly never-ending winter, summer and its bounty of produce is finally upon us. You’ll want to enjoy those gorgeous vegetables and fruit fresh of course, but when the yields grow too abundant for even the most voracious appetite to enjoy, preservation is your best bet.

Enter lactic acid fermentation, a method which not only preserves foods and nutrients but adds incomparable depth of flavour, is a total blank canvas for creativity, and promotes the growth of beneficial bacterial cultures to diversify your gut microbiome and improve general health.

1. What is fermentation?

2. What role de we play?

Fermentation is a metabolic process that microorganisms – bacterias, fungus, and yeasts – carry out when they feed off of an organic substance (vegetables, fruits, grains, pulses, beans, you name it!), resulting in a breakdown and transformation of that original substance. Those micro-critters use the medium as a source of food and turn it into their home – and by doing so, create a brand new product for us to enjoy and obtain nutrients and energy from, too.

Lactic acid fermentation is one of the most common types of fermentation – especially when it comes to fermenting vegetables – and specifically involves lactic acid bacteria (LAB) cultures. These critters thrive in anaerobic conditions (meaning in the absence of oxygen), feeding off of carbohydrates and producing byproducts like carbon dioxide and lactic acid, impacting the taste, appearance, and texture of foods.

This is a LIVE process, and if you’re fermenting in the old-school way like we’ll be discussing today (that is, by harnessing the cultures naturally present in your environment rather than adding bacteria strains that have been harvested), it is also WILD. That means that there is only so much you can control throughout the process, because those microorganism will do what they want first and foremost.

Instead of forcing these cultures into submission, we must encourage the desired microbial cultures to thrive by creating a hospitable environment for them to colonise successfully.

3. The core principles

1. Anaerobic conditions
   Lactic acid fermentation happens in the absence of oxygen. We need to make sure that our vegetables are fully submerged under liquid, with no significant pockets of air. There are two ways of accomplishing this: by drawing out the water from naturally juicy vegetables, or by making a brine and adding it over the top. More on this below.
2. Temperature
   The warmer the environment, the faster something will ferment; the colder the environment, the slower something will ferment. Room temperature is ideal for home & kitchen fermenters, allowing you to comfortably regulate fermentation activity, although you may need to adjust depending on your local climate or the season. Placing your ferment in the fridge will slow down activity and keep it stable, but will also keep the bacteria cultures alive – especially helpful when your environment is exceptionally warm (30C +) or if you’re happy with your ferment’s flavour and want to store it as it is.
3. Salt
   LAB can tolerate low quantities of salt, contrary to other undesirable microorganisms. In order to create that selective environment, we need to add some. Salt also works to slow down the rate of fermentation, helping you regulate activity level. And finally, it adds essential flavour!
4. Size of your ingredients
   The smaller the pieces, the more quickly they’ll ferment and soften. The larger the pieces, the more time it will take for the LAB to break them down, so they’ll stay crisp for longer. Remember this when you’re experimenting with vegetables, and use it to your advantage if you want to play around with contrasting textures.
5. Sugar content
   LAB feed off of carbohydrates. That means that the higher the sugar content, the more food will be available for the microorganisms, and the more active the ferment will be. Keep this in mind when you see recipes that include fruit or sweeter vegetables, such as carrots or beetroot, but don’t be wary of them either! Sweetness is a wonderful tool to help balance the acidity that will inevitably develop.

4. Self-brining vs. brined ferments

5. Equipment

Self-brining ferments are made from vegetables that hold enough water that can be drawn out to create a brine, usually by adding 2% of the total weight in salt; when the vegetables are compressed tightly in a jar, the liquid will rise and completely submerge them. This is how sauerkraut is made, but the process can be applied to other produce as well – citrus or cucumbers for example, when sliced, will create sufficient brine.

Brined ferments are fermented by making a separate salty brine and adding it over the vegetables – this is the typical process for vegetables that are fermented whole or in large chunks, such as when cucumbers are turned into gherkins. In my experience you’ll usually want to increase the salt percentage if you’re using this method (3-4%) because the salt takes longer to permeate and flavour the larger chunks, which means you’ll run a higher risk of undesirable microbes making it their home before the LAB can take hold.

You don’t need fancy equipment to ferment. A mixing bowl, scale (although some fermenters measure everything to taste!), glass jars, tea towel or cheesecloth to cover, and a blunt-tipped object to pack your vegetables into the fermenting vessel will suffice. If the mouth of your jar is large enough, you can even replace the packing tool with your fist.

Glass is the best choice for your fermenting vessel. Clay is great too, but the transparency of glass will allow you to better gauge what’s happening. Because of the acids that will build up over time you’ll want to avoid any metals, which can corrode, or plastics, which can leach.

You can, of course, invest in specialist equipment, especially for keeping the ferments submerged under liquid. Some jars have air-release valves to keep oxygen out whilst releasing the carbon dioxide build-up; you can also invest in fermentation weights to keep everything pushed down. Or, find a flat rock that fits through the mouth of your jar.

6.  Understanding time and your environment

1. When is it ready? There is no straightforward answer to this question. Not only will the pace of fermentation depend on your environment and the factors listed in part 3, but the “readiness” of a ferment is entirely subjective. What tastes appropriately tangy, funky, or fizzy to one person might be completely different to another.Your solution? Use your senses and observe, taste, and smell your ferment as it progresses. (Bacteria cultures change over the course of a ferment’s life, so if you’re looking to really reap the benefits of the live cultures and diversify your gut microbiome, you’ll want to eat a little every day anyway.) These will be the best measurement tools. Don’t be afraid to veer from a recipe’s instructions – especially on timeframes – because what works in someone’s kitchen might not translate in the same way to someone else’s.Over time you’ll come to understand what works best for you, in your environment, and with the ingredients and equipment at your disposal.
2. Use the core principles above to help you adjust your processes according to your environment. For example, if you’re fermenting in the summer or in a particularly warm climate and you’re worried about over-active fermentation, you can slow the fermentation rate by: adding a pinch or two more salt (making sure it’s still edible!), placing your ferment in a cooler place if not directly in the fridge, or adding ingredients which are less sweet. The opposite rings true: if your environment is cold, you might want to take the salt ratio down, find a warm (but not hot!) place to keep your ferments, and add some extra sources of natural sugars.

7. Safety

1. Make sure the equipment you use is clean, especially the jar you’re fermenting in. You do not need to chemically sterilise anything – wild fermentation is all about harnessing the right kinds of microbes, and if we killed all life there wouldn’t be any left to ferment our foods for us!
2. Use quality ingredients, ideally ones that haven’t been irradiated or treated with pesticides. Don’t use rotting or mouldy produce; whilst fermentation preserves our foods and their nutrients, it won’t bring them back if they’re already gone.
3. In the first week or two of fermentation, carbon dioxide production is highest. Avoid sealing your jars to avoid explosions (more common in warm environments) until you’re past this stage. Cover with a breathable cloth secured with a rubberband instead (not necessary if you have an airlock jar).
4. Even if you’ve done everything right, sometimes fermentation just goes wrong. This is the risk of working with live critters. Rely on your senses to help you determine if something is good to eat or not: if you see a colourful or black growth developing, your best bet is to toss it. And if it smells bad or off, definitely DO NOT try it. If it makes you want to throw up, chances are that it actually will.
5. There’s a certain kind of white, filmy yeast which can grow on the surface of ferments called Kahm yeast. It’s harmless so you can just scrape it off (making sure to look it up so you’re sure of your identification) but it can throw the flavour.

RECIPE: Elderflower & lemon fermented asparagus

• One bunch of asparagus
• A couple of elderflower heads
• 2 slices of lemon
• Fine sea salt
• Pink peppercorns (optional)

1. Chop the woody ends off the asparagus and discard. Place them upright into the jar and make sure they fit comfortably, leaving 2 inches from the mouth of the jar. Shorten the long ones by snapping the ends.
2. Weigh the asparagus (snapped bits and all), the lemon, and the elderflower in the jar. Fill the jar with water so everything is covered, leaving about an inch of space from the mouth of the jar.
3. Note the total weight and calculate 4% of that number; that’s your amount of salt. Weigh that into the jar, stir to dissolve, add the peppercorns if using, and cover with a tea towel secured with a rubber band (to release the CO2 build-up and keep out bugs).
4. Keep the jar on your countertop, out of the sun, and monitor every day. Push everything down daily to make sure nothing stays above water level for too long. Smell and taste regularly to assess the development of lactic acid. As the LAB take over, the brine will acidify, seasoning and gently softening the asparagus. The colour will get cloudy, and some fizz will develop.
5. When the asparagus are noticeably tangy and fizzy, but still crunchy (this happens after one week in my kitchen), pop the lid on and store in the fridge.

RECIPE: Cucumber, green bean & carrot kimchi

A self-brining ferment. Use a 500ml jar.

Ingredients:

• 3 small cucumbers
• 1 medium carrot
• 75g green beans
• 1/2 apple, grated
• 1 spring onion
• 2 large cloves of garlic
• 7g nub of fresh ginger
• Fine sea salt
• 1-2 tsp gochugaru (Korean red pepper flakes; if you can’t find, add a few pinches of chili pepper flakes instead).
• 1 tsp sesame seeds (optional)
• 1/2 tsp miso paste (optional)

1. Slice your cucumbers, shave the carrots into ribbons (making them easier to pack into your jar), and chop the green beans into 1-inch pieces.
2. Weigh the vegetables and apple and calculate 2% salt from the total amount – sprinkle that amount on top and toss the veg so they’re fully coated. Set aside.
3. Grate the garlic and ginger into a smaller bowl. Add the gochugaru flakes and miso, if you choose to use. Mix it all together to form a paste.
4. Slice your spring onion into rings and add to the bowl of vegetables. Add sesame seeds if you’re using.
5. The salt should have drawn a fair bit of water out of the cucumbers (if it hasn’t, let it sit a bit longer). Add the paste to the vegetables and mix it through to coat. Taste and adjust seasoning if necessary.
6. Now the packing stage: grab a fistful of vegetables and place in your clean jar. Pack it down using your blunt-tipped object or fist, pushing out air pockets and letting the liquid rise. Keep doing this, fistful by fistful, until you’ve left 1.5 inches from the top of the mouth of the jar. Flatten the vegetables out.
7. Clean the inside and outside of the jar so NO bits are clinging to the sides; these will invite bad microbes and spoil your ferment. Use a towel if you need to. Once the jar is cleaned and the surface flat and tidy, pour the remaining cucumber kimchi liquid over the top to create that liquid seal.
8. Keep your jar on your countertop, out of the sun, covered by a tea towel secured with a rubber band. Monitor your kimchi everyday, making sure that if any veg rises above the surface of the liquid, you push it back down (if you aren’t using weights, do this daily). Kimchi takes between 4-7 days to ferment at ambient temperature (environment dependent, of course). Taste every day, and once it’s to your liking, seal the lid and store in the fridge.

Use as a condiment, to top rice or egg dishes, and keep the brine for Bloody Mary’s.

AND FINALLY…

The one thing I stress the most during my classes is to not forget to enjoy the process, and don’t stress if you get it wrong! Making mistakes is how you’ll learn and develop your fermentation intuition. Trust your instincts, trust the LAB, and if you’re really not sure then just get rid of it and start over again.

The flavours that develop during fermentation can be truly incredible, and the potential for creation is boundless – what might seem like an accident at first might evolve into something mind-blowing. There’s a certain alchemical magic you can’t get from any other type of culinary processing! Just get experimenting.