This month I try to focus all of my posts on the science of fruits and vegetables (I call it fruit & vegetable science month!). Then, this morning, I was browsing through the internet and ran into a (Dutch) post on making your own sauerkraut! It so came to happen that I still had some white cabbage that I wasn’t sure on how to use yet. Also, just a couple of days before, when browsing through a bookstore (always nice to do), I saw this book with a lot of fermentation recipes, thinking that was something I would like to try some day.
In short, I couldn’t do otherwise than trying to make my own sauerkraut! So as I’m writing this I’ve just put the sauerkraut in a pot, ready to do some more research on sauerkraut making. Whereas I would often do the research before making something, this is one of those times I just started doing it, without really looking into it that much.
Sauerkraut = sour cabbage
Let’s start at the beginning, the name. Sauerkraut originates from the German language, literally translated it means ‘sour cabbage’, which is of course a very appropriate name. Sauerkraut is indeed sour and it’s made of cabbage. In Dutch it’s called the exact same way, though be it in Dutch: ‘zuurkool’ (zuur = sour & kool = cabbage), isn’t that great?
The cabbage becomes sour during a so called ‘fermentation’ process. During the fermentation of cabbage bacteria grow in the cabbage. These bacteria produce acids, making the cabbage sour. At a certain point the cabbage is too sour for even these bacteria to continue growing. The acidity also prevents a lot of other micro-organisms from growing, thus fermentation of the cabbage is a way to preserve the cabbage, allowing it to be stored for a longer period of time.
What do you need to make sauerkraut?
That appeared to be a very easy question to answer! I would have thought complicated pots, pans and ingredients would be required, but the opposite is true, you only need the following:
- A pot that can be closed (you should have one of those)
- A bowl
- A knife
- White cabbage
- Salt (pretty important!, don’t leave this out to reduce your salt intake, more on that later)
- Spices (I used mustard seeds, bay leaf, caraway seeds & juniper berries)
You might now be wondering how you will get hold of those bacteria to perform the fermentation of the cabbage. No worries! A cabbage contains these bacteria already. A cabbage is not sterile, so there will be a lot of micro-organisms on the cabbage actually. The trick of a good fermentation is to get the good type of micro-organisms.
The recipe I used for making sauerkraut comes from a Dutch food website. I might have changed some little things, here’s what I did:
- Cabbage - you can use any type of cabbage, I used 500g white cabbage
- Salt - use 22,5g of salt per kg of cabbage, so I used 11,25g of salt
- Spices - I used: 1 tsp of mustard seeds + 1 tsp caraway seeds + 8 juniper berries + 2 bay leafs
- Cut the cabbage is small narrow strips or use a kitchen blender to cut the cabbage into small pieces.
- Put the cabbage in a bowl and start breaking down the structure of the cabbage by massaging it with your hands, crushing it with a meat tenderizer or anything else that you have available.
- Leave the cabbage to rest for a couple of minutes. You should see some moisture coming out of the cabbage. Crush it again and make sure you have tenderized all cabbage. Do not worry if you dont yet see a lot of moisture coming off.
- Mix in the salt.
- Mix in the spices.
- Put the mixture in a bowl and make sure you press it down properly. You will notice that the volume of your mixture decreases quite a bit. If you do not see any water leaving the cabbage you have not crushed the cabbage enough.
- Leave the cabbage in a pot for several days, at room termperature. Gases will be produced so do not shut off the pot completely to prevent build up of gas. I covered up the cabbage with one whole cabbage leave. Its important to make sure that all cabbage is submerged in the water at this stage.
I must admit, I haven’t done any fermentation before, so I’m very excited to see how this will go! Unfortunately, that also means I don’t yet have any practical tips to share, but just subscribe to my newsletter to make sure you’ll receive my next updates.
Analyzing the method
Of course, I did think about the recipe in a little more detail, I like to know why I do things. Therefore, I will share some of my analysis on sauerkraut making so far:
Cutting the cabbage
Fermenting a whole cabbage will be pretty hard. It will take a long time to break down the structures of the cabbage itself and it’s hard for the salt to be present throughout the whole cabbage. Therefore we cut the cabbage in slices. In my experiment I also used a kitchen blender to chop the sauerkraut. However, I’m afraid that this has chopped up my cabbage too fine. By cutting it up too fine the nutrients in the cabbage might be too readily available for the bacteria and could lead to slime forming. Well, we’ll see what happens.
Crushing the cabbage
Crushing the cabbage helps the process of fermentation to kick off. As you might have read in my post on the texture of fruits and vegetables, plant cells have sturdy cell walls. These give the cabbage in this case structure, but also prevent bacteria from gaining access to nutrients in the cells.
By crushing your cabbage these structures are broken down, allowing water to come out and nutrients to become available.
Whereas you can leave out the spices, salt is absolutely necessary to make sauerkraut a succes. Salt has several functions in your sauerkraut. Adding salt to the sauerkraut will pull out water from the cabbage through the process of osmosis. This also softens the texture, the plant cells loose their ‘turgor‘.
Then there’s another very important reason for using salt. Salt helps preserve your sauerkraut, especially in the beginning, when there’s not a lot of acid produced yet. Too little salt and slimy and potentially pathogenic bacteria (those bacteria that make you sick) could grow in your sauerkraut. Too much salt and no bacteria will grow at all (not even the good ones you need for fermentation).