How to Make Lacto-Fermented Pickles: A Simple Brine Method

What you need

Use small, fresh pickling cucumbers, such as Kirby types, because they are firmer and have less water than slicing cucumbers. Pick ones that are as fresh as possible, ideally within a day or two of harvest, because older cucumbers go soft more easily. Wash them well, and trim off the blossom end, which contains enzymes that may contribute to mushiness.

You also need non-iodized salt such as pure sea salt or pickling salt, water free of heavy chlorine, a clean wide-mouth jar and a weight to keep the cucumbers under the brine. Common flavorings include garlic, dill heads or fresh dill, black peppercorns and mustard seed. Our fermentation salt guide explains which salts are suitable, and our fermentation weights guide covers ways to hold produce under the liquid.

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Getting the brine right

A common range for cucumber pickles is a brine of roughly 3.5 to 5 percent salt by weight of the water. A simple way to reach about 3.5 percent is to dissolve around 35 grams of salt in a liter of water, which is close to two tablespoons of fine salt per quart, though measuring by weight is more accurate than by volume because salts differ in grain size.

Stir until the salt is fully dissolved, and let the brine come to room temperature. Lower salt levels ferment faster but increase the risk of softness and unwanted microbes, while higher levels slow things down and produce saltier pickles. Our fermentation salt chart article and brine calculator guide give more detail on how to work out percentages for different jar sizes.

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Packing the jar step by step

Place garlic, dill and spices in the bottom of the jar, then pack the cucumbers in snugly so they cannot float up. Pour the brine over them until everything is completely covered, leaving about an inch of headspace at the top. Place a fermentation weight or a small clean glass dish on the cucumbers so nothing pokes above the surface.

Close the jar with a lid, an airlock lid or a loose cover, depending on your setup. A tight lid without venting can build pressure, so many fermenters either burp the jar daily or use an airlock lid. Our guide to burping jars and using airlocks covers both approaches. Keep the jar on a plate to catch any overflow and away from direct sunlight.

Timing and temperature

At typical room temperatures of about 65 to 75 degrees Fahrenheit, cucumber pickles are often ready to start tasting within three to seven days, though warmer rooms speed things up and cooler rooms slow them down. The brine will turn cloudy, tiny bubbles will appear, and the cucumbers will shift from bright green to a duller olive color. All of that is normal.

Taste a pickle after the third day, and again every day or two until the sourness suits you. When they taste right, move the jar to the refrigerator, where fermentation slows dramatically and the flavor stays relatively stable for weeks. Some people prefer a half-sour style that is stopped early, while others like a deeply sour pickle.

Keeping pickles crisp

Fresh cucumbers, trimmed blossom ends and cool fermenting temperatures are the main tools for crunch. Some traditional recipes add a tannin-rich leaf to each jar, such as grape, oak, horseradish or black tea leaves, and cooks often report that this helps firmness, although evidence is anecdotal and results vary. Keeping the jar cooler and not fermenting longer than necessary also helps.

Soaking cucumbers in ice water for an hour or two before packing can also perk them up. If your pickles still come out soft, check the salt level, the freshness of the cucumbers and the temperature, and change one thing at a time. Our article on fixing slimy or soft ferments goes through other causes in detail.

Safety and spoilage signs

Normal signs include cloudy brine, bubbles and a sour, garlicky smell. A thin white film on the surface may be harmless yeast, often called kahm, and can be skimmed off, but fuzzy, colored or hairy growth is mold. If mold appears, or the pickles smell rotten, turn slimy or feel mushy all the way through, discard the whole jar rather than trying to salvage part of it.

Use clean jars and tools, keep the produce submerged and follow a reliable salt ratio. These steps are the main protection against problems. Anyone with a weakened immune system, who is pregnant or has other health concerns should check with a doctor before eating unpasteurized fermented foods. Our fermentation safety basics article covers the wider rules.

Ways to vary the recipe

Once you are comfortable with the basic method, you can change the flavorings without changing the brine. Try a few slices of fresh horseradish for bite, a sliced hot pepper for heat, coriander seed or bay leaf for a more traditional deli flavor, or dill seed instead of fresh dill. Keep the amounts modest at first, because strong flavorings concentrate as the pickles sit.

The same brine method works for many other vegetables, including carrot sticks, green beans, cauliflower florets and radishes, though firmer vegetables may need a little longer than cucumbers. Keep each batch to one type of vegetable at first so you can judge the timing, and write down what you did so you can repeat your favorite version later.