After you’ve been brewing kombucha for a while you’ll eventually want to start experimenting with different flavorings and brew styles. One of the more popular kombucha variants is making kombucha alcohol.
There are few different angles we can cover here. We can try and increase the alcohol content in a regular kombucha brew, or we can make specialized brews – kombucha wine and kombucha beer.
We’ll cover both in this article.
First up on my list: increasing the alcohol content in regular kombucha.
How Is Alcohol Produced In Kombucha?
If you want to increase the alcohol content you first need to know where it’s coming from!
As you know, there are two actors at play in brewing kombucha – yeast and bacteria. They are continuously helping one another survive by producing things the other needs.
The yeast breaks down the sugars for the bacteria, while the bacteria builds a home for the yeast by weaving cellulose together to for a disc-like structure (also called a SCOBY.)
The process in which the yeast breaks down the sugar is called fermentation. It’s this fermentation process that produces alcohol. It’s pretty simple – the yeasts devours the sugar and spits out alcohol and CO2.
It’s the exact same process that is used in beers and wines.
The main difference with kombucha is the bacteria also feed on this alcohol and produce healthy acids. This fact complicates things a little bit. Especially if we want more alcohol.
With other home brewing, like beer for example, the process is pretty straightforward – control the yeast and you control the brew. With us, we need to control both the yeast while worrying about the bacteria at the same time!
How Much Alcohol Is In Kombucha In To Begin With?
Like with most things in brewing kombucha the answer will vary.
- What temperature did you brew at?
- How strong was your sweet tea?
- How much sugar did you use?
- Did you use a second ferment?
- How old is your SCOBY?
These factors, in addition to others, will determine how much alcohol is in your final brew. If you want a detailed explanation of the alcohol levels I’ve written a separate post:
Basically, it’s going to come down to how much you support the yeast during the brewing process.
The more you support the yeast, the higher the concentration of alcohol will be.
Take note, commercial brewers are now restricted in the amount of alcohol they are allowed to produce in store-bought kombucha. This limit is less than 0.5%. So, if you’re making the switch from commercial bottles to your own home brew, expect higher concentrations of alcohol right off the bat.
All things considered, the average home brewed kombucha is going to have alcohol levels somewhere in the range of 1-2%. With a little bit of effort, we should be able to raise this closer to 2-3%.
How Do We Measure The Alcohol Content?
As the saying goes: “what gets measured gets managed.”
How are we supposed to know when our efforts pay off? Luckily, the beer brewing community has tackled this problem long ago – all we have to do is borrow some ideas.
There are three common ways people test alcohol levels at home:
- Near Infrared
Using A Hydrometer To Measure Alcohol In Kombucha
A hydrometer is a tool that will tell you the specific gravity of your kombucha — specific gravity is a measure of the density of a liquid as compared to water.
Dissolved sugar increases the density. As the yeast consume the sugars, the liquid will become less dense and closer to the density of water. The only problem with using a hydrometer is the mathematical scales used are designed for beer and wine.
The acids produced by the bacteria when they eat ethanol is a similar weight to the alcohol. Therefore, the readings are likely to be inaccurate unless you use a specific kombucha scale. For this reason, measurements made from a hydrometer should be taken as estimations at best.
Given the inaccuracy of hydrometers with kombucha, I recommend you NOT use them.
The Better Option: Refractometer
Instead of using the weight of the alcohol to calculate the amount, a refractometer uses the refraction angle of a beam of light to determine the density of alcohol.
This means the similar weight of the acids won’t mix up the measurements. In other words, refractometers will produce a much more accurate measurement for kombucha.
The good news is, refractometers are relatively inexpensive. Definitely within the price range of must home brew operations.
If you are interested in brewing kombucha beer or wine, I’d highly recommend you pick up a refractometer. This is the best way to gauge the alcohol levels for different brewing techniques you may experiment with.
The Premium Option: Near Infrared
The final way we can measure our alcohol levels is using what’s called near infrared. This technique was developed by Anton Paar (a leading developer in brewing equipment.)
The testing technique is a little complicated and requires a background knowledge in science to fully comprehend.
Basically, it bounces different wavelengths of light around the liquid and determines the quantity of alcohol by the reflections of the wavelengths.
The major downside to this method is it’s expensive. Beyond what I would consider a reasonable amount for most home brewers.
With the cheaper option of refractometers available, I have a hard time recommending anyone try this option.
How To Increase The Alcohol Content In Regular Kombucha
So, we know how the alcohol is made, and we know how to measure it. Now the only thing left to do is actually make it happen.
Before we just in, I just want to make sure everyone’s expectations are ground. Remember how I mentioned the bacteria in kombucha make it a little more complicated than beer and wine?
Well, it’s because of this bacteria that the alcohol levels are almost self-regulating. That is to say, the more alcohol that is produced, the more the bacteria will gobble it up and produce their healthy acids. That’s why most home brewers aren’t able to produce the alcohol levels much over 3%.
But, we still can increase the levels beyond what would naturally occur. The first trick we’ll use involves the second ferment.
Increasing Alcohol During The Second Ferment
If you don’t know what the second ferment is, read my article and then come back.
The second ferment gives us a perfect opportunity to bump up the alcohol levels. The way we’re going to do this is by adding in a second source of sugar. This will force the yeast into a second round of fermentation.
The trick here is to get the timing right so the bacteria doesn’t have a chance to change all of the alcohol into acids.
What you need:
- Kombucha bottles (read this post here)
- Source of sugar
- Fridge (click my affiliate link right he…just kidding :))
I recommend using some kind of fruit sweetener. Not only will it allow you to play with different flavor combinations, but it will provide the yeast a nice supply of fructose. Fructose is a great source of sugar for yeast because it doesn’t have to work as hard to break it down compare to more complex sugars.
Using regular kombucha bottles (16 oz) you want about 1 tablespoon worth of fresh fruit. Experiment with whatever you’d like – kiwi, orange, strawberry, raspberry etc.
If you are using juice, I like using 4 tablespoons.
Let the bottles sit at room temperature for 4-5 days. Then, immediately place them in the fridge.
The idea is to slow down the bacteria by decreasing the temperature of the kombucha. This forces the bacteria into a kind of “hibernation” – leaving you with plenty of extra alcohol sitting in the bottle.
It also has the side effect of producing a very fizzy kombucha!
Another method to increasing the alcohol content is add more yeast.
Adding More Yeast To Kombucha
If we know more yeast results in more alcohol, it makes complete sense to just try adding more yeast to the brew. Now, we don’t want to go around adding any sort of yeast we can get our hands on.
We’re looking for yeast that is proficient at producing alcohol.
Say hello to Turbo Yeast – yeast specifically chosen for its ability to pump out the alcohol levels. The only downside is it can taste terrible.
This is why I only recommend using 1/4 teaspoon for every 16 oz bottle. Because we want to use the primary ferment to develop the kombucha flavor, we want to add the extra yeast in during the second ferment.
Before you mix the yeast in with the kombucha, it’s a good idea to activate it by mixing it with a warm water and sugar mixture (1.5 ounces). You want to let this mixture sit for at least 30 minutes until it is foaming.
I also recommend pairing it with the first tip of adding in some fruit. This will provide the sugars needed for the extra yeast as well as help mask the unwanted flavors.
Leave this yeast in the second ferment for between 5-7 days. Burp your bottles every few days to make sure you’re not building up too much carbonation.
The Three Pronged Approach
Finally, there are three more tricks we can do during our regular brew that will help increase the alcohol content.
- Take the starter liquid from the bottom of the hotel
- Add extra sugar to the primary ferment
- Increase the temperature while cutting off the oxygen
1. Using Starter Liquid From The Bottom
For more brews, I recommend taking the starter liquid from the top of the vessel, or SCOBY hotel. The top of the vessel usually has the right balance between the acid to yeast ratio that supports the growth of the new brew.
However, if we want the most alcohol possible, we want to go where the yeast hangs out – at the bottom!
Scooping up the starter liquid from the bottom will add a significant amount of extra yeast to your new brew. When the older yeast begin to pass their prime they tend to sink and collect at the bottom of the vessel. You can usually see this process in action through the formation of a brown layer of spent yeast.
This is exactly where we want to be scooping from. This old yeast, once reawakened with a new source of food, will begin producing higher concentrations of alcohol much sooner compared to starter liquid taken from the top.
2. Add In An Extra Cup of Sugar To The Primary
Instead of adding the sugar into the secondary ferment, you can add an extra cup of sugar (assuming you are using batching in a 1-gallon vessel.)
This way, if you are completing the second ferment inside the vessel instead of bottles you will have that extra fuel to support the yeast.
This won’t work as well if you only use the starter liquid from the top of the hotel or vessel. You need that extra yeast to break down this sugar into ethanol and CO2. Using regular strength starter liquid will only lead to a very sweet kombucha.
3. Increasing The Temperature And Cutting Off The Oxygen
This final technique is likely the most advanced and carries the most risk. During the second ferment, we typically just leave the bottles to rest at room temperature for a number of days. This trick involves increasing the temperature to blast through that extra sugar we added in step 2.
The temperature increase will support the yeast while cutting off the oxygen supply will force it into instant fermentation.
Warning: increasing the temperature has the potential for increased risk of your bottles exploding.
If it’s your first time, you’ll want to burp at least 1 bottle to check on the carbonation levels. Increasing the sugar and temperature will increase both the ethanol as well as the CO2. Be careful!
Because of the increase in temperature, you’ll want to cut down on the number of days of your second ferment. I recommend only letting them rest for 3-4 days max.
How are we going to increase the temperature?
The best way to do it is by using a heat mat. Ideally, you want to heat the upper levels of the bottles, but this is difficult to do in practice. Our best alternative is to place the bottles on top of the heat mat. Set the heat mat so the temperature within the bottles is at the ideal temperature for kombucha (78-82°F.)
Do not place the bottles in the oven! This will lead to a kombucha explosion!
As usual, you’ll cut of the oxygen supply using the right bottles or vessel container. Just make sure you cool the bottles down in the fridge right after the second ferment is complete to prevent the bacteria from gobbling up all that alcohol we worked so hard to produce.
If after all of that, you still aren’t satisfied with the levels of alcohol, you’ll want to try producing Kombucha wine or beer.
How To Make Kombucha Wine
If you’re looking for kombucha that has an alcohol content over 5% then we need to start talking about making kombucha wine. I’m confident you’ll be presently surprised with the result!
It’s a more advanced brewing process and you’ll need to purchase a few specialized ingredients and equipment. But, if you’re up to the challenge, let’s get started!
Here’s what you’ll need:
- 1 gallon Carboy
- Blow-off tube
- 2 teaspoons wine yeast
- 1 cup of sugar
- 6 oz. fruit concentrate
- 1 gallon of brewed kombucha
- 5 wine bottles with corks
- Large funnel
The two essential pieces of this process are the carboy and the champagne yeast.
Choosing The Right Carboy For Kombucha Wine
Carboys are another piece of equipment borrowed from the other home brewing disciplines. Basically, it’s a large glass jug that prevents the oxygen from reaching the brew during the secondary ferment – exactly what we need!
Most of the other sites showing how to make kombucha wine recommend you use an air-lock with your carboy. While their ideas are sound, it’s a much better idea to use a blow-off instead.
Use a blow-off instead of an airlock
The reason being is kombucha tends to get bubbly in the carboy. This tends to bubble up into the airlock, forcing you to take it off and clean it.
Using a blow-off tube, on the other hand, allows for the kombucha to be as bubbly as it wants. It simply vents out this additional head and continues on fermenting.
I’d recommend starting out with a 1-gallon carboy. This translates nicely from 1-gallon batch brewing. The size of your carboy will determine the size of your blow-off tube.
I recommend sticking with a glass carboy if possible. This way you won’t have to worry about the plastic leaching into your kombucha. You can read more about choosing the right vessel material in this post:
Finding The Right Yeast For Wine Kombucha
There are a few different types of yeast you can use for increasing the alcohol content in kombucha. They are:
- Wine yeast
- Champagne yeast
- Ale yeast
For our purposes, we want to stick with wine yeast for now. This will produce alcohol levels between 10-15% ABV. It will also help promote the flavor profile we’re looking for.
Wine yeast can be found at your local wine brewing store, or online. If you want a higher concentration of alcohol in your wine then I recommend using champagne yeast. This will bring you somewhere between 15-20% ABV.
Once you’ve collected all of the equipment, it’s time to start the brewing process!
1. Activate The Yeast
Before adding the yeast into the carboy, you want to activate it first. For a 1 gallon carboy, you’ll want to use 2 teaspoons of wine yeast. Mix the yeast in with the water and the 1 cup of sugar. The sugar is needed so the extra yeast has plenty of fuel for fermentation.
Let this mixture sit until it starts to bubble and foam. This can be anywhere from 30 minutes to an entire day at most.
Once it’s activated, it’s time to mix everything into the carboy.
2. Mix Everything Into The Carboy
Mix the brewed kombucha, fruit concentrate, and activated yeast into the carboy. Stir everything until it’s well mixed.
If you want more a fruity flavor to your wine use more fruit concentrate. Use up to 12 oz. total. You can use grape, or papaya, or whatever flavor you think will work well.
Next, take the blow-off tube and insert it snugly into the mouth of the carboy. Place the other end of the tube in a bowl of water – completely submerging the end. This creates the airtight seal required to cut off the oxygen supply to the yeast.
It’s a common technique used among home beer brewers.
3. Let The Carboy Ferment
Let the mixture ferment for at least 5 days. It should be placed in a warm, dark location out of the sunlight. The ideal temperature is between 72-80°F.
If your house is slightly cooler you can always place your carboy on top of the fridge, or use a kombucha heating mat.
4. Bottle The Wine Kombucha
After 5 days, it’s time to bottle.
Old wine bottles will work perfectly fine. Just make sure you have corks that will fit snugly inside the bottle. You should be able to fill up 5 wine bottles if you are using a 1-gallon carboy.
Once the kombucha wine is in the bottles and the corks are snugly in place, it’s time to store the wine in a cool, dark location.
You can store this wine for as long as you wish. The longer the wine is in storage, the drier the flavor will be. I’d recommend you drink the wine before 1 year or else it usually becomes too tart. If you’re eager to try, you’ll want to wait at least 2 weeks.
This gives the yeast enough time to get through all of the sugars.
I’m excited to hear how it turns out for everyone. If you try it make sure to report back in the comments on what you used and how everything went!
How To Make Kombucha Beer
Lots of companies are now coming out with a kombucha beer. They’re great to try, but it’s even more fun to brew some yourself. It’s not hard!
There are two ways you can use to make your own kombucha beer:
- During the second ferment
- Using a carboy
If you want a more serious kombucha beer you will have to use the carboy method. However, if you are just wanting to experiment with the idea, or try out a few test flavors, using the second ferment method is a better idea.
The second ferment method also doesn’t require any other additional equipment besides the basics.
Using The Second Ferment Method
This method is actually very simple. Here’s what you need:
- Flip-top bottles
- 1 oz beer hops
In the same way you would add fruit to the bottles during the F2 you can add beer hops. For every 16 oz bottle you will want to use 1 teaspoon of beer hops.
You can also mix the beer hops with cut up fruit, fruit juice, or fruit concentrate if you’re looking for more of a saison flavor.
Do not use the hops for more than two days.
The main difference with using beer hops is the ferment time. You really only want to have the beer hops in the kombucha for 2 days max. By all means, test your brew for flavoring before you remove them, but anything over 2 days runs the risk of becoming too bitter.
If you still want higher levels of carbonation you can continue the second ferment without the beer hops.
Using The Carboy Method
The carboy method is very similar to the wine making process outlined above. Instead of using wine yeast, you can use larger yeast, or ale yeast. Depending on the strength you are looking for.
Ale yeast will usually produce a stronger flavor – akin to brewing ales, porters, stouts, Altbier, Kölsch, and wheat beers – whereas lager yeasts will produce a milder kombucha beer.
I’d recommend using an ale yeast if possible. This yeast is better suit for fermenting at the temperatures we are used to working with (60-70°F). Lager yeast, on the other hand, is better suited to fermenting at much lower temperatures (below 30°F)
You can skip the fruit juice if you’d like, or use something like a grapefruit concentrate for a summer beer.
Along with the beer yeast you will have to add 1 oz of beer hops during the initial carboy mixing phase.
Similar to the second ferment method, you only want to leave the hops in carboy for 2 days max. Any more and the kombucha will become unbearably bitter.
Let the carboy ferment with the blow-off hose installed for 5 days. Taste after 5 days to get a sense of the flavor. If it’s still too sweat, let it ferment for a couple more days.
Then, bottle the beer in flip-top bottles and store in a cool, dark location for at least 1 week. Similar to the wine, the longer you let them sit, the drier the flavor will become.
Let me know if you try this and how everything goes! I’d be interested to hear what recipe you used and how things turned out.
If you have any questions, please ask them in the comment section below.
Until next time!