Brine fever: Swetha Sivakumar takes the lid off pickles from around the world

The word “pickle” is said to have come from “pekel”, the Dutch word for brine. Even today, the ingredient that forms the base of every type of pickle is salt.

Is salt alone enough? Technically, yes. But it takes a salt-to-produce ratio of 1:4 to prevent microbial growth, and this makes for a very unidimensional flavour. So people eventually found ways to use less salt and still preserve fresh produce. They did this by cutting off oxygen supply (oxygen allows microbes to thrive, speeds up browning, causes fat molecules in food to go rancid), by submerging the produce in fermented liquid, vinegar or oil.

To this day, when they say “pickle” in the West, they mean vegetables preserved in vinegar. The pH levels of most vinegars stands at about 2.4. (pH values are measured on a range of 0 to 14, with anything less than 7 indicating acidity, 7 indicating a neutral liquid, and anything over 7 indicating a base liquid). Bad bacteria find it very difficult to grow in a pH of less than 4.5.

The acidity in vinegar also keeps hemicellulose (or plant fibers) from breaking down, thus helping pickled produce retain its crunch and consistency. Vegetables and fruits suspended in vinegar can have a shelf life of up to three months. Unopened pasteurised jars have a two-year shelf life. Even water-heavy vegetables such as cucumber can be pickled in vinegar, without salting excessively, because of vinegar’s low pH. The most common such pickles, in fact, include the water-heavy gherkin (with dill for added flavour), and pickled onions.

In parts of Europe and south-east Asia, there’s another popular method used to reduce pH levels to less than 4.5, and that’s lactic-acid fermentation. This is how pickles such as sauerkraut and kimchi are made. Here, vegetables such as cabbage, radish and carrot are sliced and salted (in a 2% to 5% concentration) to draw the water out. The vegetables are then pressed into a ceramic jar full of the brined juice. The lactic acid bacteria in the environment start to turn the carbohydrates in the vegetables into lactic acid. The more the vegetables ferment, the more the pH levels drop, which protects the vegetables from going bad. However, at some point, the whole mix must be put in a refrigerator or a cool cellar or the pickles can get too sour to eat.

This kind of pickle is great for gut health. Kimchi samples have been found to contain levels of probiotic lactobacilli comparable to those in commercial probiotic yoghurts.

Now for our Indian pickles. These are made by adding salt and spices to vegetables (or cured fish or meat), then submerging the mix in oil. Normally, this would seem like a strange thing to do. Vegetables contain water. Oil and water literally do not mix. Plus, wouldn’t the oils themselves spoil?

This is precisely why traditional Indian recipes recommend sesame or mustard oil; both are rich in natural antioxidants. The relatively high levels of salt (15% to 20% by weight) keep water-activity levels low too. Added spices such as fenugreek and mustard contain bitter phenolic compounds that act as natural antioxidants. All these together help keep the mix from spoiling.

As with the other pickle recipes, almost anything can be preserved in this manner. Acidic items such as lime and amla are easiest to preserve. Less-sour items such as lime, garlic, brinjal or drumstick, pork or fish are sundried or fried first, to reduce moisture content.

Given the high salt levels, these pickles are best eaten in moderation. But when it comes to complexity and flavour, in my opinion at least, our pickles win hands-down. What would thair sadam (curd rice) be without elumichai oorugai (lemon pickle), or khichdi be without mango achaar?