Finding the Best Temperature for Sauerkraut Fermentation

May 19, 2025

If you’re trying your hand at making sauerkraut for the first time, you’ll likely picture jars filled with that tangy, crunchy goodness. But the reality can sometimes fall short, leaving you with a less appealing product, perhaps a slimy texture or a layer of mould. Despite following the right salt-cabbage ratio, you might have overlooked a crucial aspect in the fermentation game: Temperature.

This blog will explore why temperature plays a critical role in the transformation of cabbage into delicious sauerkraut. You will also discover the best temperature for sauerkraut fermentation and learn a few practical tips to maintain it effectively.

So, let's ensure your kraut ferments beautifully, avoiding unpleasant tastes and textures, by finding that perfect thermal sweet spot!

What is sauerkraut?

Sauerkraut is simply fermented cabbage, a culinary staple that has been enjoyed across various cultures for its tangy flavour and numerous health benefits. With a few simple ingredients and a natural fermentation process, you can transform the humble cabbage into a probiotic-rich delight.

The journey of making sauerkraut begins with mixing finely shredded cabbage with salt. This salty environment draws out the cabbage's juices, creating a brine in which naturally occurring lactic acid bacteria thrive. These beneficial microbes feed on the sugars present in the cabbage and produce lactic acid as a byproduct.

This lactic acid gives sauerkraut its distinctive characteristics:

Taste: It delivers that signature tangy and acidic flavour, often developing a pleasant complex profile over time.
Texture: The desired outcome is a wonderfully crisp and crunchy texture, providing a satisfying bite.
Probiotics: The fermentation process transforms the cabbage into a powerhouse of beneficial bacteria (probiotics), which are known for their positive impact on gut health.
Natural preservation: The lactic acid produced acts as a natural preservative, inhibiting the growth of undesirable microorganisms and ensuring the sauerkraut's longevity.

Let’s look at the nutritional profile of sauerkraut per 100 grams:

Nutrient	Amount per serving
Calories	19 kcal
Carbohydrates	4.7 g
Fiber	2.9 g
Protein	0.9 g
Sodium	661 mg
Vitamin C	14.7 mg (24% of the Daily Value)
Vitamin K	13 mcg (16% of the DV)
Iron	1.5 mg (8% of the DV)
Potassium	170 mg (5% of the DV)

Are probiotics really the solution to better gut health? Listen to the co-founder of The Good Bug speaking about its benefits and impact in the video below.

Speaking of fermentation, let's talk about why temperature plays such a pivotal role in the process.

Why is temperature important in sauerkraut fermentation?

You might think salt and time are the only main players in sauerkraut making. However, temperature is a surprisingly critical factor that ultimately determines the success and quality of your kraut.

Here’s why getting the temperature right is so important:

Bacterial activity: Temperature impacts the activity of the beneficial lactic acid bacteria. If warmer temperatures speed up their metabolism and growth, cooler temperatures slow them down. The ideal range allows these good bacteria to thrive and develop a complex, appealing flavour and a crispy texture.
Lactic acid production: The rate at which lactic acid is produced and the specific types of acids that develop are influenced by the ambient temperature. This directly impacts the final flavour of your sauerkraut.
Competition with unwanted microbes: Maintaining an ideal temperature creates an environment that favours the growth of lactic acid bacteria while keeping undesirable microbes at bay. Too high or too low temperatures can encourage their growth, leading to off-flavours, mushy textures, or unsafe products.
Speed of fermentation: Temperature is a key determinant of how quickly your sauerkraut ferments. If warmer temperatures accelerate the process, cooler temperatures will slow things down. Fermenting at the right temperature can lead to perfectly crafted sauerkraut with the right flavours and texture.

Also read: Making Sauerkraut Without Salt: A Simple Recipe Guide

Ready to hear about the magic number? Let's pin down that ideal temperature for fermenting sauerkraut!

What is the ideal temperature for fermenting sauerkraut?

Finding the best temperature for sauerkraut fermentation is the secret to a successful ferment. The ideal temperature range for fermenting sauerkraut lies between 60°F and 70°F (approximately 15°C to 21°C). However, the sweet spot lies around 65°F (approximately 18°C) to achieve the optimal flavour and texture development.

Going beyond this ideal temperature zone can lead to less desirable outcomes in your fermentation journey:

If the temperature is too warm (above 70°F or 21°C), the fermentation process can accelerate too rapidly. This can result in the production of off-flavours, a less complex taste profile, and a mushy texture due to the overactivity of certain enzymes. It can also create a more hospitable environment for harmful microbes, potentially spoiling your batch.
If the temperature is too cold (below 60°F or 15°C), the fermentation process can significantly slow down or even stall altogether. Besides leading to a weak or less pronounced flavour, this can increase the risk of spoilage due to the lack of enough acid production by the lactic acid bacteria.

Also read: The Roots of Kraut: Where Did Sauerkraut Come From?

But how does this temperature influence each stage of fermentation? Let's break it down.

How temperature influences the different stages of sauerkraut fermentation?

The journey of cabbage to sauerkraut is a fascinating one, guided by a succession of microbial players, and temperature acts as the conductor, influencing each stage of this fermentation process. Understanding how temperature affects these different stages can provide valuable insight into achieving that perfect kraut.

Stage 1 (Days 1-5): The initial takeover by Leuconostoc mesenteroides

This initial phase is characterised by the rapid growth of Leuconostoc mesenteroides, the smallest of the three lactic acid bacteria involved in sauerkraut fermentation.

As soon as you mix cabbage with salt, these microbes consume the sugars and produce lactic acid, acetic acid, carbon dioxide, enzymes, and mannitol (a flavour compound). The production of carbon dioxide is crucial as it helps create the anaerobic environment necessary for successful fermentation by pushing out oxygen.

Here’s how temperature significantly impacts this stage:

Warmer temperatures can hinder the ability of Leuconostoc mesenteroides to produce the initial acids and flavour compounds effectively, potentially leading to a less complex final flavour.
Colder temperature slows down its activity, delaying the creation of the necessary anaerobic environment and increasing the risk of spoilage by other microbes.

Stage 2 (Days 5-16): Lactobacillus plantarum takes the lactic acid lead

As the acidity increases, Leuconostoc mesenteroides activity slows down, and the more acid-tolerant Lactobacillus plantarum takes over as the dominant lactic acid producer. This lactic acid bacteria efficiently converts sugars primarily into lactic acid, further lowering the pH and contributing to the preservation of the sauerkraut.

The optimal temperature range allows Lactobacillus plantarum to thrive and produce lactic acid at a steady rate, contributing to the desired tanginess and preventing the growth of spoilage organisms:

Too warm, and this stage might proceed too quickly, potentially affecting flavour complexity.
Too cold, and Lactobacillus plantarum will be sluggish, prolonging the fermentation and potentially increasing the risk of unwanted microbial activity.

Stage 3 (Days 16-21): The Final Touches by Lactobacillus brevis

In the later stages of fermentation, another lactic acid bacterium, Lactobacillus brevis, becomes more active. It contributes to the final flavour profile by producing lactic acid as well as other compounds.

The environment is now palpably acidic and the bulk of the preservation has been achieved by this point. However, the temperature can influence the subtle nuances of the final flavour:

Cooler temperatures during this phase might lead to a more complex flavour development.
Warmer temperatures could result in a simpler, more straightforward lactic acid profile.

So, how long should you be keeping an eye on your kraut? Let's talk about timelines!

How long does sauerkraut ferment?

The fermentation duration for sauerkraut is not a one-size-fits-all scenario; it varies primarily with the ambient temperature. Typically, sauerkraut fermentation spans anywhere from 2 to 6 weeks. However, this is a broad range, and the actual duration will largely depend on the ambient temperature:

Warmer temperatures, around 70-76°F (21-24°C), will encourage faster bacterial activity. In these conditions, your sauerkraut might reach its desired level of tanginess and texture in a shorter timeframe, often within 1 to 2 weeks.
Cooler temperatures, around 60-65°F (16-18°C), will slow down the process. It will take 4 to 6 weeks or even longer for the bacteria to produce the necessary acids and for the flavours to develop fully.

Ultimately, the most reliable way to determine when your sauerkraut is ready is by tasting it regularly. Look for a balance of tanginess that suits your preference and a texture that is softened but still retains some pleasant crispness. Let your taste buds be your guide; they'll tell you when your sauerkraut has reached its perfect fermented state.

Also read: Preserving the Tang and Crunch: How Long Will Sauerkraut Last?

No temperature-controlled room? No problem! Let's see some easy tricks to keep your sauerkraut cozy, no matter the season!

How to control the temperature for sauerkraut fermentation?

Maintaining the right temperature for sauerkraut fermentation can be a bit of a challenge, especially with fluctuating weather conditions. However, with a basic stick-on thermometer or by monitoring your room's ambient temperature, you can create a stable and welcoming environment for your kraut to thrive.

Let’s look at more actionable tips for keeping your sauerkraut stable!

Tips for warmer weather

When the temperatures rise, keeping your fermenting sauerkraut cool is key to preventing overly rapid fermentation and potential off-flavours. Here are some helpful tips:

Seek a cooler sanctuary: Identify the coolest area in your home. Basements or lower floors tend to maintain lower temperatures, offering a more stable environment for your ferment.
The icy embrace: Place your fermentation jars inside an ice chest or a large container. Surround the jars with frozen jugs of water or ice packs. Replenish the ice as it melts to maintain a cooler temperature.
Sunlight is the enemy: Always ensure your sauerkraut jars are kept away from direct sunlight. It can significantly raise the temperature inside the jar, disrupting the fermentation process.
Short and sweet ferments: Fermentation will proceed at a faster pace during warmer periods. So, consider a shorter overall fermentation time to prevent it from becoming too sour or developing undesirable textures.
Stone cold comfort: Place your fermentation vessel on a cool surface like a stone or marble slab. This can help dissipate some of the ambient heat and keep the ferment slightly cooler.
Airflow assistance: If you have air conditioning or a fan, utilise them to lower the overall room temperature. This can create a more favourable environment for your fermenting sauerkraut.

Also read: Delicious Pairings: What Goes Good with Sauerkraut?

Tips for cooler weather

When the temperature dips, providing a little extra warmth can help maintain the optimal range for your sauerkraut fermentation. Here are some gentle warming techniques:

Warmth up high: The top of your refrigerator often generates a small amount of warmth from the motor, which can be a slightly warmer spot compared to other areas in your home.
The seedling saviour: Place your fermentation vessel on a seedling heat mat, which is commonly used for starting garden seeds. Use a thermostat controller to maintain a stable temperature and prevent overheating.
Oven (unplugged with light on): An unplugged oven with just the oven light turned on can create a surprisingly gentle and consistent source of warmth. Monitor the temperature inside to ensure it doesn't get too hot.
Near a gentle heat source: Position your fermenting jar near a gentle heat source like a radiator or a warm corner of the room. Ensure it's not in direct contact, which could cause the temperature to fluctuate too much.
Insulation station: Wrapping your fermentation vessel with a towel or a small blanket can help insulate it and retain existing warmth, providing a more stable temperature environment.

Thus, temperature is more than a number on a thermometer—it's the guardian of sauerkraut's taste, texture, and health benefits. Don't let fluctuating weather be a barrier to your sauerkraut dreams.

Experiment with these tips to find the best temperature for your sauerkraut fermentation. With a little attention to temperature, you can consistently produce delicious, probiotic-rich sauerkraut right in your kitchen, no matter the season.

Are you ready to skip the temperature guesswork and enjoy perfectly fermented sauerkraut? Explore The Good Bug's expertly crafted sauerkraut, bursting with flavour and beneficial probiotics. Visit our website to order your jar and discover a delicious and convenient way to nourish your gut!