A divisive issue: fridge or no fridge?

When you start making homemade kombucha, one of your first concerns is:
what do you do with your SCOBY when you’re not brewing?

As you read blogs and forums, you come across two opposing camps:

On the one hand, there are those who say:
“Put your SCOBY in the fridge, it’ll put it on pause”.

On the other hand, there are those who say:
“Don’t do it! You’ll kill it, keep it at room temperature”.

Result: you’ve got your SCOBY of kombucha – perhaps a freshly-arrived SCOBY Natural Probio – and you’re hesitating. You’re going on holiday, you’re short of time, or you simply don’t want to brew for a few weeks… and you don’t know what to do.

The truth is more nuanced. You can technically put a SCOBY in the fridge, but it’s neither the magic solution nor the ideal method in most cases. Depending on how you do it, the fridge can :

• usefully slow down crop activity
  
• or, on the contrary, tire it out, weaken it and complicate its reactivation
  

In this article, we will :

• explain what the cold really does to a SCOBY
  
• see in which cases the fridge should be avoided
  
• detail the rare situations in which it can be of service
  
• offer safer alternatives, such as theSCOBY hotel
  
• give you a reactivation method if your SCOBY has already been in the fridge
  

The aim is simple: for you to know when and how to use (or avoid) the fridge, to keep your culture healthy and ready to brew living kombucha, especially if you’re working with a Natural Probio strain.

The first thing to understand is that a SCOBY likes gentle heat, not cold.

Before talking about refrigerators, we need to go back to the very nature of SCOBY.

A living ecosystem, not an “object”.

A SCOBY of kombucha is not just a gelatin disc that you put somewhere. It’s a living biofilm, made up of :

• yeast
  
• acetic bacteria
  
• other beneficial bacteria
  
• a cellulose matrix produced by these micro-organisms
  

This ecosystem functions optimally in a mild temperature range, generally between 20 and 26°C. This is where :

• yeasts consume the sugar in tea
  
• they produce alcohol and gas
  
• bacteria convert alcohol into organic acids
  
• a new film of SCOBY forms on the surface
  

This is what happens in your jar when you make homemade kombucha with SCOBY Natural Probio in a temperate kitchen.

What the cold weather means for farming

The refrigerator is designed to slow down microbial life. At around 4°C :

• yeast barely works
  
• acetic acid bacteria slow down
  
• exchanges within the biofilm become very limited
  

The SCOBY is not necessarily “dead” in these conditions, but it is almost asleep. If the cold continues :

• some cells can die
  
• the balance between yeast and bacteria can change
  
• reactivation on return to room temperature becomes more uncertain
  

To sum up: SCOBYs don’t take well to major temperature shocks and don’t like living in a fridge for long.

Why we want to put a SCOBY in the fridge… and where the pitfalls lie

It’s no coincidence that so many people think of the fridge. At first glance, the idea seems logical.

Reasons for using the refrigerator

We tend to think of the fridge for several reasons:

• we’re going on holiday for a long time
  
• we’re worried that the kitchen will be too hot in summer
  
• we don’t want to “deal” with the SCOBY for a while
  
• we think that the cold will “stop” the fermentation and keep the culture intact
  

On paper, it looks like a simple solution:
“I’ll put it in the fridge, and I’ll find it as is in a month.”

The reality: a break that is neither neutral nor gratuitous

In practice, this “break” in the cold is not neutral:

• the drop in activity doesn’t preserve the culture, it plunges it into a different kind of stress
  
• the most fragile cells can die
  
• condensation, temperature variations and jar handling create micro-shocks
  

When it’s time to take the SCOBY out of the fridge, you’re sometimes left with :

• fermentation that restarts very slowly
  
• kombuchas that aren’t very fizzy, flat or even unbalanced
  
• a SCOBY that takes several batches to regain its vigour, but when it does
  

So it’s not a real ‘perfect backup’, but rather a solution of last resort, to be used with caution.

When is it better to avoid the fridge altogether?

There are several scenarios where the fridge is clearly a no-go for your SCOBY, especially if you’re working with a healthy strain like the one supplied by Natural Probio.

At the start of a new crop

When you have just received a SCOBY :

• the crop acclimatises to your water, your tea, your sugar
  
• the first fermentations bring a new balance to your kitchen
  
• the biofilm has not yet had time to strengthen its defences
  

Put it in the fridge at this stage:

• breaks its momentum
  
• weakens its installation
  
• extends the time needed to obtain stable kombucha
  

On the contrary, it’s better to bake a few times at the right temperature to consolidate the lineage.

For short or medium breaks (a few days to a few weeks)

Many novice brewers think :

“I don’t brew for a fortnight, I put the SCOBY in the fridge straight away”.

In reality, for a break of a few days to 3-4 weeks, it is much healthier to :

• leave the SCOBY in a jar at room temperature
  
• immersed in highly acidic kombucha
  
• may be fed occasionally with a little sweet tea if the break is prolonged
  

The fridge does nothing in this case, it simply adds unnecessary heat stress.

If the environment is not acidic enough

Putting a SCOBY in the fridge in a sweet, slightly acidic tea is particularly risky:

• to the cold, beneficial cultivation slows down
  
• if the pH is still relatively high, certain undesirable bacteria or yeasts can survive
  
• with warming, these opportunistic micro-organisms can regain the upper hand
  

Before any chilling (if you really have no choice), the SCOBY should be surrounded by kombucha, which is already quite acidic and the result of complete fermentation.

When can the fridge still be of service?

Now that the framework has been established, we have to be honest: there are some specific situations where the refrigerator can be a lesser evil.

Rare case no. 1: very long absence with no possibility of interview

Assume that :

• you are going away for several months
  
• no one can look at or feed your hotel in SCOBY
  
• your home is at risk from extreme temperature variations
  

In this case, leaving a jar at room temperature, unattended, may be more risky than placing part of your culture in the fridge, in a very acidic medium, in the hope that it will survive in idle mode.

This does not guarantee perfect reactivation, but it can be an extra safety net, in addition to other measures (giving a SCOBY to a relative, for example).

Rare case n°2: extreme heatwave and lack of options

If you live in an environment where the indoor temperature can rise well above 30°C for a long time, and :

• you don’t have a cooler room, cellar or temperature-controlled cupboard
  
• you’re worried that prolonged heat will weaken the crop more than the cold
  

then, under very strict conditions, refrigerated storage of a fraction of the SCOBY can be envisaged as a back-up solution.

But then again, it has to be :

• a SCOBY placed in a very acidic liquid
  
• time-limited storage
  
• an exceptional measure, not a habit
  

How do you put a SCOBY in the fridge in the least risky way possible?

If you’ve understood the limits but are in a case of force majeure, here’s how to minimise the risks.

1. Prepare a highly acidic storage medium

Never use simple sweetened tea to store in the fridge. Instead, prepare :

• a clean glass jar
  
• fill it mostly with well-fermented, almost vinegary kombucha
  
• check that it smells clearly of kombucha or vinegar, with no suspicious notes
  

You can add a small amount of cooled sweet tea, but the essential liquid must be very acidic, to keep the pH low and protect the SCOBY.

2. Choosing the right piece of SCOBY

Don’t put your entire bloodline in the fridge. Keep :

• a young, clear, supple record
  
• preferably recently formed on the surface of a successful batch
  

Leave other discs in a SCOBY hotel at room temperature, if you can. This will increase your chances of recovering a healthy crop when you return.

3. Fully immerse the SCOBY

Place the SCOBY in the jar of acidic kombucha:

• it must be completely covered with liquid
  
• no part of the liquid that could dry out or become mouldy in contact with cold, damp air
  

Avoid jars that are too narrow or too wide, where the SCOBY could stick to the sides and partially emerge.

4. Use a suitable cover

In the fridge, you can :

• use a simple or very lightly screwed-on lid to avoid fridge odours
  
• or, failing that, a taut film
  

The jar does not need to be ventilated as much as at room temperature, as activity is very low. The main aim is to protect the culture from odours and possible contamination.

5. Limit the time you spend in the fridge

The longer SCOBY stays cold, the more :

• some cells die
  
• the balance of the microbial community deteriorates
  

If you can limit the time in the fridge to a few weeks, that’s better. After 2-3 months, the chances of full reactivation of the culture diminish significantly.

How do I reactivate a SCOBY that has come out of the fridge?

Imagine you’ve already stored your SCOBY in the fridge, or you’ve received it from someone who’s been keeping it there. How do you give it a real chance to restart?

Step 1: gently wake him up

Don’t suddenly move from the fridge to a very warm room. Take the jar out:

• Leave it to cool to room temperature (for a few hours)
  
• avoid thermal shock (no hot baths, no direct radiators)
  

Observe:

• the smell of the liquid (it should remain vinegary/kombucha, not rotten)
  
• the appearance of the SCOBY (no mould, no coloured fluffy patches)
  

If anything looks seriously wrong (mould, putrid smell), it’s best not to attempt reactivation and to start again with a healthy SCOBY, for example a new Natural Probio culture.

Step 2: Place it in an ideal environment

To give the SCOBY the best chance of getting back on track:

1. Prepare a classic sweet tea for kombucha and leave to cool completely.
   
2. Pour the tea into a clean jar.
   
3. Add a good quantity of very acidic kombucha (the storage liquid, if it smells good, can be used in part).
   
4. Carefully transfer the SCOBY to the new jar.
   

In this way, you create a :

• nutritious (sugar)
  
• Protective (acidity)
  
• at room temperature
  

Step 3: Accept that the first batch is a “working” batch

A SCOBY out of the fridge won’t necessarily produce immediately:

• flavoured kombucha
  
• very sparkling
  
• perfectly balanced
  

The first batch after reactivation is often used to :

• revive the microbial community
  
• stimulate the production of new films
  
• reconstitute a coherent yeast/bacteria balance
  

You can :

• taste the evolution of the liquid
  
• leave to ferment until you obtain a very acidic kombucha
  
• you may not drink this first batch and use it as a kombucha mother for the next one
  

The second or third batch often has a more satisfactory profile.

Why a room-temperature hotel in SCOBY is almost always preferable

For the vast majority of home brewers, especially with a quality culture like a SCOBY Natural Probio, the best alternative to the fridge is the SCOBY hotel.

Storage that’s alive but secure

A hotel in SCOBY :

• keeps discs in acidic kombucha
  
• keeps them at a moderate room temperature
  
• allows a light renewal of sweet tea from time to time
  
• avoids extreme thermal shock
  

Under these conditions, your line of kombucha :

• stays alive
  
• continues to produce new films from time to time
  
• remains ready for use at all times
  

If you need to take a break for several weeks or months and still have the opportunity to take a look at the jar from time to time, the hotel at SCOBY is far superior to the fridge.

Real security in the event of a problem

With a SCOBY hotel, you can keep several disks:

• some younger
  
• others older
  
• sometimes cut into pieces to increase the chances of success.
  

If one day :

• a batch gets contaminated
  
• a jar breaks
  
• you have doubts about the health of a particular SCOBY
  

you can return to your hotel and start afresh with a clean slate, without having to rely on the hypothetical survival of a SCOBY that’s been in the fridge for months.

Frequently asked questions about the fridge and SCOBY

To clarify things even further, here are a few frequently asked questions.

Should I put the finished kombucha in the fridge?

Yes, but it’s not the same thing.
Bottled, ready-to-drink kombucha keeps very well in the fridge:

• cold slows down fermentation
  
• fizz stabilises
  
• taste develops more slowly
  

Putting the drink in the fridge is normal.
Putting the culture (SCOBY) in the fridge is a different story, with the precautions we have seen.

Can I leave my SCOBY in a sealed bottle in the fridge?

It’s not ideal.

• in a closed bottle, oxygen is very limited
  
• fermentation can produce gas that cannot escape
  
• the SCOBY can deform, stick to the walls, or even run out of air in the core
  

If you really have no other option for short storage, make sure you don’ t fill the bottle completely, and open it from time to time to release any excess pressure. But on the whole, a larger jar is still much more suitable.

My SCOBY has spent a long time in the fridge and looks “dead”. What can I do?

“Death” is a strong word. If :

• the smell is always right (vinegary, kombucha)
  
• no visible mould
  
• the SCOBY simply looks inert
  

it’s worth trying to reactivate it by following the steps outlined above.

However, if :

• the smell is rotten
  
• coloured fluffy patches are present
  
• the liquid is visibly contaminated
  

it’s safer to throw it all away and start again with a healthy SCOBY. That’s when a new Natural Probio culture or a disc from a well-maintained SCOBY hotel makes all the difference.

In practice: what does Natural Probio recommend for the fridge?

Summing up everything we have seen, the reasonable position is as follows:

• For short breaks (a few days): leave the SCOBY in its acidic kombucha, at room temperature, in a protected jar.
  
• for medium breaks (a few weeks): set up a rest jar or SCOBY hotel, with a little sweet tea added from time to time
  
• for long breaks (several months) with the possibility of minimal maintenance: SCOBY hotel, always at moderate room temperature
  
• in extreme cases (prolonged absence, heatwave with no alternative, no-one to take a look): consider using the fridge only as an emergency solution, putting only part of the culture in a very acidic medium, accepting that reactivation will not be 100% guaranteed
  

For a brewer starting out with SCOBY Natural Probio, the aim is not to look for complicated solutions, but to :

• understand that culture prefers gentle heat to cold
  
• quickly set up a maintenance routine at room temperature
  
• always keep a little acidic mother kombucha and, ideally, a small hotel in SCOBY
  

So you use the fridge where it excels – to store your bottles of ready-to-drink kombucha – and you keep your SCOBY in the environment it prefers: a glass jar, acidic kombucha, a temperate temperature, a living kitchen.

Conclusion: the fridge isn’t the enemy, but it’s not the SCOBY’s home.

The question “Can you put a SCOBY in the fridge?” calls for a qualified answer.

Yes, it can be done, technically.
But no, it’s not the best way to look after your crop in most situations.

The fridge :

• slows down activity, but at the cost of stress for the crop
  
• complicates reactivation, especially after a long stay
  
• is only useful in cases of force majeure
  

For everything else, room temperature care and a well-managed SCOBY hotel remain the safest, simplest and most respectful solutions for the living nature of kombucha.

By working with a quality SCOBY, such as those offered by Natural Probio, you’ll soon discover that the key is not to “chill” everything, but to learn how to support living things: provide them with a stable environment, feed them from time to time, observe their behaviour and build a relationship of trust with your jar.

The day you open a new bottle of kombucha, sparkling, balanced, born of a culture that you’ve been able to keep in shape month after month, you’ll see that this patient care was worth much more than the apparent ease of the fridge.