Lacto-fermentation

Why lacto-fermentation?

There are many reasons! Among them: lacto-fermentation provides the basis for many of the world's favorite ferments, such as kimchi and sauerkraut. Beyond that, I think lacto-fermented fruit can be some of the most interesting tasting (in a good way) stuff you can find.

Getting started

I think the most fun way to get started with this one is to ferment plums; they're relatively easy and provide the most consistently good results of any fruit I've tried. One important note: fermentation people will often say that the product you get out can only be as good as the product you put in. I generally agree with this, although the extent to which it is true seems to vary considerably with what type of ferment you are doing. With lacto fermentation, it matters a lot. In my opinion, it's usually not worth lacto-fermenting something that isn't already (very) tasty.

So, go find yourself some delicious plums. Then, cut them in half and cut out the pits. Weigh the plums (do you have a kitchen scale?), and add 2% of the total weight of the plums in un-iodized salt. Then, put the plums and salt in a jar, mix them around a little, and wait! To prevent mold (your primary enemy here), it's good to mix the plums around with a spoon every day or two. Depending on temperature and freshness of plums, they will start to bubble aggressively in 3-7 days. Taste them frequently, and use when they're delicious! They can be a little intense on their own, but go great with dairy products, like on ice cream or in a milkshake.

What's going on here?

Lactic acid bacteria eat sugar and produce lactic acid, which acts as a preservative. It happens to be that some lactic acid bacteria are very tolerant of salty environments. So, when you add a bit of salt, you are basically selecting for these bacteria, which then produce lactic acid to further prevent the growth of other microbes. Sometimes in high-sugar environments (as with fruit) you can also get significant yeast activity, and your ferment can smell alcoholic. This is fine (i.e. not harmful), but can be undesirable flavor-wise. To prevent this, you can start with a slightly higher salt percentage, but this will affect the taste of the final product.

More general technique

Coming soon...