Can you freeze sauerkraut?

In years past, people left sauerkraut out on the counter and used it as a condiment, as needed.

These days, with better knowledge of food safety, leaving sauerkraut out on the counter isn't so safe. So many people are looking for a way to help the sauerkraut keep longer.

What is sauerkraut?

Sauerkraut is traditionally made with finely shredded white cabbage in brine which is fermented. The signature sour taste and its long shelf life are thanks to the lactic acid build-up as a result of the fermentation process with lactic acid bacteria.

The unique flavour of sauerkraut is a definite draw for people, but so are the many bacteria that can help to keep your digestive system healthy and functioning.

As I said, sauerkraut is fermented. Fermentation is a process that helps to preserve all sorts of foods. It's particularly used for things that are in abundance in the summer months so they can still be enjoyed in the winter. In the case of sauerkraut, the bacteria that feast on the sugars of the cabbage turn it into lactic acid, which helps to give it its familiar taste.

Can you refrigerate sauerkraut?

You don't always have to refrigerate sauerkraut, but it will keep it fresher for longer. This is because sauerkraut is still in the process of fermentation, so the longer you have it, the more it will ferment.

Equally, warmer temperatures will increase the rate of fermentation. So if you prefer your sauerkraut to have more crunch, you should refrigerate it.

One of the main things to consider when you store sauerkraut is limiting the amount of air that can get to it. So push down any extra sauerkraut so it's fully submerged in the brine.

If you've got a big jar half full in the fridge consider transferring it to a smaller sterilised jar so there isn't a big air pocket at the top. It will help it last longer and take up less space in the fridge too.

If you do have an overwhelming supply of sauerkraut and would like it to stay fresh so you can enjoy it later, store it in the freezer and follow the step by step instructions below to freeze your sauerkraut safely.

Are there different types of sauerkraut?

So, where to start? The first thing to note is what kind of sauerkraut you have. If you've brought it from the chilled section of a shop or made it at home and never cooked it then it's both fermented and still fermenting.

You put it in the fridge to slow this process down as generally the warmer the container the more energy bacteria have. The more energy the bacteria have the more fermentation there is.

However, too much fermentation will start to negatively affect the taste/ texture, eventually leading to spoilage. So you should try to slow down the fermentation by cooling it down in the fridge.

A jar or tin bought from a shelf of a shop will have been fermented, then pasteurised (brought up to a hot enough temperature to kill most pathogens), which makes it safe to store at room temperature until open, but has also killed essentially all the bacteria that was fermenting the cabbage.

Make sure your sauerkraut is food safe

Freezing pasteurised sauerkraut is best when it is freshly opened to reduce the risk of any unwanted bacterial growth. This is particularly important if you intend to freeze tinned sauerkraut as they tend to have less preserving liquid.

Always follow the use-by date and make sure you're freezing before this.

If you're freezing unpasteurised sauerkraut (homemade or from the chilled section) make sure it still looks pale yellow and has no obvious signs of spoilage. If it's turned a greyish colour this means the fermentation process has gone beyond what would be pleasant to eat and potentially dangerous -and this won't improve in the freezer!

Prepare sauerkraut for the freezer

Not much preparation is involved in freezing either kind of sauerkraut. Basically, just scoop the sauerkraut into freezer-safe containers or freezer-safe bags with as little liquid as possible and squeeze out as much air as you can.

The smaller amount of liquid means the quality of the vegetable won’t be as compromised once thawed.

To make thawing easier, try freezing your sauerkraut in single-serving portions.

The best container to freeze sauerkraut

It’s fine to use either a freezer-safe container or freezer-safe plastic bags. Making sure as much air is out of either container as possible is important to reduce the risk of bacterial spread as well as freezer burn.

Don’t forget to label your containers with the date you popped them in the freezer. As stated above, freezing your sauerkraut into single-serving portions will help not only thaw it faster but let you only thaw what you need.

Make sure you've sealed your containers well and try and keep them upright so no leaking occurs before it’s frozen.

How long can you freeze sauerkraut?

If frozen safely and correctly, your sauerkraut should still be delicious after 2-3 months, but can be frozen for up to six months. The quality and taste may diminish after the three-month mark, so it’s better to use it sooner rather than later.

How to defrost frozen sauerkraut

When you are ready to enjoy your frozen sauerkraut, there are a few ways to defrost it:

• Put the portion desired into the refrigerator overnight, this is an important step. If you take this route, the sauerkraut can be stored in the fridge for an additional 3-5 days.
• If you want to defrost on the countertop, follow these steps. It may take a few hours, depending on the portion size you’re defrosting. So you can speed up the process by placing your container or bag in a bowl of cold tap water. Please make sure your container or bag is sealed well before using this option. Use the sauerkraut immediately after thawing.
• You know you can microwave sauerkraut to defrost it. Microwave on the defrost setting in 10-second increments until fully thawed. You will want to use it immediately after.
• Place it directly into a dish you want to cook in. This method works especially well in soups. Just make sure you add a few minutes of cooking time. This is to make sure the sauerkraut thaws completely and comes up to temperature.

Dishes to cook with your frozen sauerkraut

Frozen sauerkraut is delicious in tons of recipes. If you have tired of using it as a plain side dish, try it as one of these options:

• A classic is to use sauerkraut as a topping for burgers and hotdogs. However, it works fantastically in wraps and salads too!
• You can jazz up avocado toast with sauerkraut instead of chilli for an interesting kick.
• Mix it with cream cheese or hummus to change up the flavours of your usual dip
• Put it on sandwiches instead of pickles. Think ham, cheese, mustard and sauerkraut? Yum!
• Add an extra jolt of flavour to your soup or mashed potatoes.

For more tips on freezing food to reduce waste, check out my other how to freeze food articles.