Recipe: Sauerkraut

Humans have been using lactofermentation to process and preserve food for thousands of years. Long before we had the ability to sterilize or refrigerate perishables, people all over the world were submerging food in brine to encourage friendly bacteria cultures to proliferate. Not only do these "good bacteria" keep the "bad bacteria" from rotting perishables, many of them are the same microbes that help our guts stay healthy. In addition, fermentation makes certain nutrients in food more bioavailable, meaning the nutrient content is effectively higher.

The best part of lactofermentation? It's really easy to do. Food is submerged in salty liquid for days or weeks until the process is complete. And that's pretty much it. Nerds like me appreciate the elegance of the science involved: Food rots when aerobic (air-loving) bacteria break down protein in the presence of oxygen, however by submerging food in liquid, oxygen is dramatically reduced. In this environment anaerobic (air-hating) bacteria thrive and fermentation occurs. Using salty liquid further limits which bacteria can proliferate, and fortunately the good, gut-friendly bacteria is salt-tolerant. As food ferments in a salty, low oxygen environment, lactic acid is produced. The acidity gets so high that bad bacteria species can't survive and thus the food is preserved. This acidity is also what gives lactoferments their pleasantly sour flavor.

Vegetable fermentation is a safe and ancient activity. Here is some more information about the food safety issues if you're nervous - but by all means if you don't feel comfortable culturing bacteria in your kitchen, then don't.

- 1 medium sized white cabbage (approximately 2 lbs)
- 2 tbsp. pickling salt, sea salt or any other salt without additives (avoid using iodized salt or "free-running" table salt)

1) Wash cabbage thoroughly and remove any wilted outer leaves or leaves with bad spots. Thinly slice and place in a large, non-reactive (ie, not metal) bowl.

2) Add salt and massage it into the cabbage for 5 minutes. Within a minute it should start to feel wet and slippery between your fingers as the salt starts to pull out water from the cabbage.

3) Pack the cabbage down into the bowl and leave it for 15 minutes to let it sweat out more water.

4) Transfer the cabbage into a glass jar. A canning funnel will make this a much faster and less messy job. Depending on the size of your cabbage you'll need a 1 or 1.5 L jar. The cabbage should be tightly packed into the jar, with a 1-2 inch space at the top. Push it down with your fingers to squeeze out as much air as possible.

5) Once you've fully packed in the cabbage, all of it should be underneath the brine. If not you can top it up with a little bit extra in the ratio of 1 cup water to 2 tsp. salt. Distilled water is the best choice as some municipal water treatments can discourage fermentation.

6) After the cabbage is fully submerged in brine you'll need to weigh it down with something to keep as much air out of the jar as possible. You can use a jar or a small plastic (food grade) bag. Either option should be washed thoroughly beforehand and half filled with water to increase the weight. Place the jar on a small plate in a cool spot of your kitchen (ie, not in front of a sunny window).

7) Within 48 hours you will start to see bubbles around the cabbage. This is carbon dioxide and is a by-product of lactofermentation so don't worry that oxygen has gotten inside your jar. Some brine will inevitably spill out of the jar as a result of this bubbling and the expansion of the cabbage as it ferments, but as long as everything is still completely covered in liquid it's ok. If you need to you can add some extra brine back in (1 cup water to 2 tsp salt).

8) After one week the bubbling will have slowed down and the cabbage turned from light green to pale golden in colour. Take the weight off and test a piece of sauerkraut. It should taste sour, salty and crunchy. Keep it out on the counter and taste it every day (you can put a regular lid on now, but make sure the cabbage is still submerged in liquid). It will continue to mellow and develop in flavor.

Sauerkraut purists will tell you to keep it out for at least four weeks to allow the full, multi-stage cycle of fermentation to occur. I think the common sense approach for newbies is to refrigerate once it's reached the flavor you really like. It will continue to ferment in the fridge, just more slowly. Once refrigerated your sauerkraut can last for several months. If the veggies become discoloured, slimy, or foul smelling discard the batch. A thin layer of white mold on the very surface can be safely skimmed off so long as the veggies still smell and taste ok.