Guest Post by Dave H: Kohlrabi Kimchi

Thanks to Allie for inviting me to be a guest author here. I'm so delighted to be sharing my recipe for kohlrabi kimchi today. Kimchi is one of my favorite fermented foods, and kohlrabi is one of my favorite vegetables, so when you put the two of them together, I am one happy camper!

Kohlrabi is a foreign vegetable to many people, sort of resembling the Russian satellite called Sputnik that was launched in the 1950’s. While it looks like it might be a root vegetable, the edible part is actually the swollen aboveground stem. The name comes from the German Kohl (cabbage) and Rübe or Rabi (turnip). I’ve seen its flavor described as being like broccoli, cabbage or turnips, but to me the flavor of kohlrabi is mild and hard to classify. There’s nothing there not to like though, and I’ve been eating it and growing it in the garden for a long time. For the last few years I have also been fermenting it, which adds a whole new level of flavor to this otherwise mild-mannered vegetable.

Kohlrabi has an outer skin that can be green, white or even purple. The flesh inside is crisp and juicy with a creamy white color. For fresh eating, smaller ones around 3 inches in diameter are more tender and flavorful, but for fermenting it really doesn't matter. The larger ones do just fine, and I even grow big varieties specifically for fermenting. Whatever size you have will make great tasting kimchi.

Now for a bit about equipment. You don't need a lot of expensive gear to make kimchi. I generally ferment most vegetables in a glass Mason jar, including kimchi. I find the wide mouth jars are easier to work with and get my hands into. They are also relatively inexpensive, easy to clean, and last forever. Fido style jars are also popular, and for larger amounts fermenting crocks are a good choice. I use food safe and BPA-free plastic caps on the jars, which fit loosely and don't require burping to allow the fermenting gases to escape. Glass or ceramic weights are also useful to keep the veggies submerged under the brine, which is important to keep surface yeasts and molds from forming. I always remember the cardinal rule of fermenting - under the brine and all will be fine! There are other tricks to keeping things submerged though, and one of my favorites is using a leaf for a "topper". For kohlrabi kimchi, a couple of the leaves will do the job to keep the kohlrabi covered.

I learned early on that there are likely as many recipes for kimchi as there are people making it! There is no clear-cut consensus as to what ingredients to include, or how long to let it ferment. I've never visited Korea, so my experiences with eating it have all been in the U.S. Most were extremely hot and spicy - too much so for my tastes, and some weren't even fermented at all and used vinegar for pickling. There are a few common ingredients though, like ginger, garlic and hot pepper flakes. And the vegetables are typically soaked in a salty brine solution before adding the seasonings, though some recipes call for dry-salting. I love to experiment, and I tried several recipes and did a lot of tasting before I came up with one that suited me.

When developing this recipe for kohlrabi kimchi, I relied heavily on my version of cabbage (baechu) kimchi and radish (kkakdugi) kimchi. One of the key ingredients in my recipe is Korean hot pepper flakes, called gochugaru. They can be found in many Asian markets, as well as online. I learned early on (the hard way) not to substitute with cayenne powder. Gochugaru usually has a mild or medium heat level, while cayenne and some other peppers are typically way hotter. There are different types of gochugaru powders with different heat levels depending on which peppers are used, which lets you control the level of spiciness of your homemade kimchi. I like using a milder powder which lets me use more of it, and that also helps give it that characteristic red color. So, with all that in mind, let's get started making a batch of kohlrabi kimchi!

Kohlrabi Kimchi (for one quart)

1 1-/2 pounds (675-700 grams) of peeled diced kohlrabi

Green onions or chives (optional)

Brine solution:

Un-iodized salt

Filtered water

Seasoning Paste:

1/2 cup onion, chopped

1/2 tsp fish sauce

1/2 tsp soy sauce

6 garlic cloves, peeled

2″ piece of ginger

1/4 cup gochugaru flakes (more or less to taste)

First off, I wash the kohlrabi and cut off the leaves (save a couple if using as a topper). Then I peel the kohlrabi and cut it up into cubes about 1/2 to 1 inch or so in size. It will take about 1 1/2 pounds (675-700g) of cubed kohlrabi to fill a quart jar. Next, I soak the cubes in a 5% brine solution for 8 to 12 hours. It's important to use a non-reactive container like stainless steel or glass for the brining.

To make the brine, I weigh the water and salt using an electronic scale set to weigh in grams. Any un-iodized salt will do. I generally use either a fine Himalayan pink salt or a sea salt, and 50 grams of salt in 1000 grams (one litre) of water will get you a 5% brine. You can scale it up or down as needed for larger or smaller batches. I use filtered tap water to make sure chemicals used to treat the water don't affect the fermenting process. The amount of salt doesn't have to be exact, and you can use 3 level tablespoons of fine salt in a quart of water if you don't have a scale. After the kohlrabi has brined, I drain in a colander, saving some of the liquid brine for use later. Now it's time to make the seasoning paste.

I like to use fresh ginger, onion and garlic along with the dried gochugaru flakes for the paste. I also add a bit of fish sauce and soy sauce to supply an umami flavor. Some recipes call for all kinds of ingredients, including fruits like pears, apples or even pineapple. And dried shrimp or anchovies are often included instead of fish sauce. I think part of the fun of making your own is to experiment, and how I’m making it today may not be the way I make it next year or the year after that as my taste change. Most of the ingredients for the paste should be readily available, and the gochugaru usually isn't too hard to find.

I coarsely chop the onion and ginger, then put in the bowl of a food processor or mini chopper along with the peeled garlic, gochugaru, fish sauce and soy sauce.  Then I blend until it forms a smooth paste, using the reserved brine to get the desired consistency.

One thing I do like to add to this kimchi is either green onions or chives, especially if you have the flat leaf kind of chives. It's optional, but I find they do add a little flavor and color to the finished ferment. For a quart jar, one or two green onions should do or a couple of tablespoons of chopped chives.

Now it's time to mix the seasoning paste into the drained kohlrabi, and add the green onions or chives. You can use your hands or use a spoon like I did.

When it's well mixed you pack it into the jar, pressing down until it's firmly packed and there are no air spaces. There should be at least an inch of headspace in the jar to allow for expansion during fermentation. The kohlrabi mix should be covered with the wet seasoning paste, and if you need more liquid you can add some more of the reserved brine. Top with weights if using, or you can use one of the kohlrabi leaves to make a "topper" that covers the surface of the ferment.

I let the kimchi ferment in the jars for about two weeks before refrigerating. Recipes are all over the place when it comes to how long to let it ferment. The longer you let it ferment, the sourer the taste will be. Longer ferments also allow the various flavors to develop, and the heat can actually mellow a bit. Warmer temperatures will speed up the pace of fermentation, while cooler temps will slow it down. It’s a good idea to begin tasting the kimchi after four or five days, and refrigerate when it suits your tastes. It will continue to ferment in the refrigerator, but at a much slower pace. If kept cold and covered in brine, my kimchi keeps for at least a year - though it's usually eaten up long before that! I have a bit left from a jar I made almost a year ago, and while the kohlrabi has gotten a little soft and the bright red color has faded, the flavor is outstanding.

I hope this has inspired you to try your hand at making this delicious fermented vegetable. I should add that you need be careful though - I find kimchi of all kinds to be habit-forming! That's not a bad thing though.