How Temperature Affects Kombucha Brewing Flavor

One of the most important variables you need to control when fermenting Kombucha is the temperature.

Temperature affects three things:

1. the fermentation time
2. the bacteria-yeast ratio.
3. the flavor (because temperature affects fermentation time and the balance between yeast and bacteria, it also influences the flavor of your brew)

While brewing at the best temperature is not the ONLY thing that will affect your Kombucha flavor profile, it’s also one of the most important AND easiest variable to control. To control your brewing temperature, read our following articles:

• How to Brew in Hot Temperatures
• How to Brew in the Cold
• Brewing in Warm Weather
• Brewing in Cold Weather
• How to Counter Seasonal Effects When Brewing

The Possible Brewing Temperature Range

You can brew Kombucha in temperatures anywhere from 50 F to 108 F. This is a rather extreme range of temperatures. What’s impressive is that this shows how hardy the SCOBY is. Your SCOBY can survive (and even reproduce) given some dramatic temperature shifts.

However, survivable temperatures is not the same as ideal temperatures. If you brew at the upper and lower temperature ranges, you won’t get very good Kombucha.

Placing your Kombucha near the lower and upper limits of this range (or above or below them) will result in horrible tasting Kombucha, very long fermentation times, no fermentation, and/or the possibility of mold contaminating your culture.

But even more important is that by targeting different temperatures, you can push the flavors in a specific direction, thus giving you more control over the taste profile of your Kombucha.

There are a few reasons why you might want to control the temperature to target a specific range

• increase fermentation time to brew more quickly
• target a specific preferred flavor profile (stronger full flavored kombucha, lighter sweeter kombucha, or a mild flavored kombucha)
• rapidly increase your SCOBY production
• to compensate for external factors (cold or hot weather, SCOBY age, the type of tea)
• adjust the yeast to bacteria ratios to favor one or the other

The Ideal Kombucha Brewing Temperature

We often tell you to brew your Kombucha in the ideal temperature of 76-78 degrees.

However, there’s actually a wide range of temperatures, you can brew at that will give you a great tasting Kombucha.

While brewing at 76F – 78F may give you the best consistent flavors, you actually can brew great Kombucha between 69-84 degrees.

The reason is that you may want to brew at the low end of 69-70 or the high end 80-84, depending on what you are trying to achieve with your brew, the state of your SCOBY (is it an old or new one), and your flavor goals.

The bottom line is that you should know exactly what brewing at specific temperature ranges will do to your brew, both to the fermentation time and the overall flavor, so you can adjust your buch brewing to meet a flavor target.

Temperature Extremes & Kombucha Flavor

Both at the lower temperature and at the higher temperature range, Kombucha, the yeast cultures can overpopulate the brew due to the reduced activity of the bacteria. However, as long as there’s no mold present in the brew, and there is fermentation, you can still drink the Kombucha, though you may not enjoy the flavor.

Lower Temperature Effect on Taste

Lower temperatures tend to give a weaker tasting brew that’s often sweeter. SCOBY formation may be retarded and thin. At the very low temperatures, no SCOBY will form and there will be no fermentation process.

Higher Temperature Effect on Taste

Higher temperatures tend to give sour tasting brews with a strong, sharp bite.

The Affects of Temperature on Kombucha Flavor

Temperature is one of the most important factors that affect your Kombucha brew. It’s also one of the factors that with a bit of planning you can control. Because of this, you should.

Here’s a list of all the possible temperatures ranges between 50 F and 108 F and what you can expect to happen with your Kombucha at certain temperature ranges between these extremes. Note that there is no definite ‘right or wrong’ for what temperature you want to brew at.

Some people enjoy how Kombucha tastes when brewed at 69F, while some enjoy brewing at 89F (I’ve done a fair bit of brewing at 100F). The bottom line is that there’s a good degree of variability in how Kombucha may taste and what sort of taste you want.

We suggest about 77 F as the ideal temperature because at this temperature you get the most consistent, stable brew. But that doesn’t mean you can’t brew better tasting Kombucha at a higher or lower temperature.

As long as the culture is not contaminated by mold and some fermentation happens, you can drink it.

 108F + (42C)

“The Death Zone”

At this temperature the yeast itself will begin to die. Your SCOBY won’t be able to survive more than a few sustained hours at this temperature; even if you remove the SCOBY, the culture may still die or be damaged.

Flavor: horrible. What you are drinking is not Kombucha anymore but sweet tea and dead microbes.

96F – 108F (35C – 42C)

“Yeast Heaven & Bacteria Hell”

At the lower range (95-96F) is about the temperature where the bacteria in your culture will begin to die. Even if you fix the temperature, brewing for a few days at about 100 may cause a complete imbalance between the bacteria and yeast populations that will affect your brew.

By the upper range of this (108F), the bacteria will be dead and the yeast will begin to die too. You’ll get a fermentation, but it won’t taste good due to the overactive yeast and inactive bacteria. The taste will be sour and yeasty.

To get a decent tasting brew, you should brew below 100F (38C). Occasional spikes in temperature above this by 5 or 6 degrees F are fine. However, you don’t want to brew for long period of time above 100F or you’ll get a horrible tasting brew or, if temperatures are above 105F, no proper fermentation at all due to the yeast and bacteria all dying. I have done quite a bit of brewing Kombucha in the tropics (Thailand) at about 90-105 and my Kombucha comes out fine. You just need to make sure you keep a close eye on the fermentation times as it brews far quicker and tours sour faster.

Flavor: sour vinegary flavor with very strong yeasty tones.

85F – 96F (29C – 35C)

“The I Love a Very Strong Ferment”

This temperature range inhibits bacterial development and promotes overactive yeast. As a result the ratio between yeast and bacteria will fall into imbalance with more yeast than bacteria. You can get away with one or two brews at this temperature range, but repeatedly brewing in this range will cause the yeast to completely overtake the bacterial cultures. Fermentation time is very short (with the brew turning sour quickly) which means you have a strong acidic profile but a low level of nutrients produced by the bacteria due to the very quick fermentation time.

Flavor: very strong full flavored kombucha with mild to strong yeasty tones.

80F – 84F (26C – 28C)

‘The I’m Impatient Ferment”

This is on the higher range of the ideal brewing temperature. You get quicker fermenting brews that are more powerful in taste. There’s a more concentrated level of acids in the brew when you ferment at this temperature due to the quicker fermentation time. Because the fermentation is rapid, the bacteria has less time to work and the brew will likely have less organic acids and beneficial nutrients than when you ferment at a lower temperature. Newer SCOBYs do well in this range, but older SCOBYs may give more sour-tasting brews.

Flavor: mild to strong full flavor kombucha with a medium to strong tart. Some might call this a fruity flavor.

76F – 79F – (24C – 26C)

“The Perfect Buch”

This is the ideal temperature for brewing Kombucha and the range where there is a perfect balance between yeast and bacterial populations. You get a good level of organic acids produced by the bacteria due to the moderate ferment time. Brewing at this range gives you the healthiest combination of organic acids and nutrients due to the slow fermentation time.

Flavor: sweet to mild full flavor kombucha with medium tart. 

70F – 75F (21C to 23C)

‘The Soft and Sweet Ferment”

This is on the lower range of the ideal temperature. You get a sweeter kombucha that’s less acidic. This range is good for more mature SCOBYs (the cultures are not as vibrant). Due to the lower temperature range, it may take longer to brew than normal. You will get a high amount of nutrients produced by the bacteria, however, due to the slower fermentation time.

Flavor: sweeter, smooth tasting kombucha with less bite. If you don’t like tart or the stronger flavors of Kombucha, this temperature range is ideal for you.

64F – 69F (17C to 20C)

“The Slow Fermenter”

This temperature range inhibits bacterial growth with stronger yeast production. Fermentation time will be slower and the SCOBY growth may be weak and thin.

However, you can still brew great tasting Kombucha in this range, especially if you are willing to wait weeks for the ferment to finish. You may want to store your SCOBY hotel in this temperature range due to the slower fermentation, however. If you brew during fall or spring, this is the temperature range you may experience.

Flavor: sweet and soft with a mild tartness. May have a slight yeasty aftertaste, especially if you brew at the lower range of the temperature (64F).

59F – 63F (15C – 17C)

“SCOBY Hotel Heaven”

The middle of this range (59-61) is the ideal range for long term storage of your SCOBY hotel. Why? Because storing your SCOBYs at this range will allow you to go months (2-4 months) without needing to refill with fresh sweet tea. Brewing in this temperature range won’t produce very good Kombucha, especially below 60F.

50F – 58F (10C – 14C)

“Super Slow Ferments”

Very long fermentation times with very weak SCOBY growth. Bacterial activity, especially near the 50F range is halted which increases the risk of a mold infestation taking hold. You don’t get good tasting ferments at this temperature and it takes months to ferment your brew.

Flavor: sweet and weak flavored

Below 50F (10C)

“Do Not Drink This”

No fermentation occurs. Because the bacteria become inactive and the yeast are barely active, your culture is at risk of a mold infestation. Note that this is about the temperature range inside of your fridge (fridges range from 30-40 degrees F).

Which brings us to one more point: do NOT put your kombucha with a SCOBY in the fridge to ‘pause’ the fermentation.

This means don’t put a SCOBY in a bag, or a bottle of fermenting kombucha, or a SCOBY hotel into your fridge. Kombucha won’t go ‘bad’ when you leave it out — it just becomes more sour and acidic. But leaving your Kombucha out won’t ‘spoil’ it, but putting your SCOBY + Buch into the fridge will.

Why shouldn’t you put your SCOBY into the fridge?

The reason you should never refrigerate your SCOBY being that at this temperature, the yeast and bacteria in the SCOBY will go into a deep ‘sleep’; which can lead to mold developing in your brew when you try making a new batch with the SCOBY (or you try to ‘ferment’ that buch again).

If you do manage make a new brew with a refrigerated SCOBY, you’ll often get a flat, barely fermented brew for a few cycles. Sometimes you won’t be able to ferment at all. Even more insidious, is that the possibility of mold developing is very high, because the culture is very weak.

Flavor: You’re drinking sweet tea with a possible dose of mold.