Continuous Brewing – Grow Your Pantry

Continuous Brewing

by Susan Grey on November 17, 2019
continous_brew_art

 

What is continuous brewing? It refers to a setup that can ferment kombucha continuously without having to switch the SCOBY with each new batch. With this you can enjoy kombucha on tap thanks to the larger brewing volume. The brew needs to be replaced with the same amount of fresh sweet tea to replace the kombucha that's been harvested.
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Batch Brewing vs. Continuous Brewing

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While both of these brew methods do offer certain advantages, the best way to use both systems is by using them where they are the best fit.

What's the difference between batch and continuous?

Batch brewing - This involves taking apart the entire brewing setup after a brew is ready. The process would then be repeated, and some of the brewed kombucha mixed in with the fresh sweet black tea, and the SCOBY added. Batch brewing makes typically around half a gallon of kombucha, depending on the size of the fermentation vessel. If you wish to brew another batch, you will have to set it up once more as it cannot accommodate continuous brewing. 
Continuous brewing - This relies on using a larger fermentation vessel to accommodate a more substantial amount of brewing kombucha (we suggest 2 to 5 gallons). This process takes much longer to produce the first brew as the volume of sweetened black tea used takes about 14 days to brew. As a result, this system can be making kombucha continuously for up to 6 months.
Advantages Of Continuous Brewing:
  • Brews more kombucha as the only limit is the size of your container.
  • Once the setup has attained an optimum brewing rate, it can brew quicker, taking less than 72hrs.
  • Less contamination as the SCOBY doesn't get moved during maintenance (maintenance required at least twice per year).
  • Having a spigot makes it much easier to bottle the kombucha.
  • The system also acts as a SCOBY hotel, so you don't have to take it apart when you are away or busy.
  • It offers a hassle-free brew method that doesn't require weekly maintenance top off with a similar amount of tea as the extracted kombucha.
Disadvantages Of Continuous Brewing:
  • It takes longer before the first brew ferments completely- around 14 days compared to 5 to 7 days in batch brewing.
  • The spigot is much more prone to getting blocked by the yeast that floats at the bottom.
  • When needing maintenance, it is much more time consuming compared to batch brewing. However, it is done less frequently.
  • When left for too long the SCOBY could die due to the growth of mold or dehydration.
  • It's much more costly to set up compared to batch brewing.
Advantages Of Batch Brewing:
  • Batch brewing takes up less surface space.
  • Batch brewing is best for first-timers, it's a much simpler setup.
  • If you have a baby SCOBY batch brewing offers a much faster way to grow it.
  • Batch brewing offers the opportunity for experimental batches.
Disadvantages Of Batch Brewing:
  • Requires the entire setup to be taken apart after each batch.
  • Decanting and bottling kombucha prepared in small quantities can be quite messy and time-consuming.
  • There's a higher chance that the SCOBY will get contaminated or grow molds due to frequent handling and exposure.
  • Batch brewing can be quite hectic when brewing a large amount of kombucha as you will have to deal with multiple containers and varying fermentation times.

Why Continuous Brew Kombucha?

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The continuous method offers a hassle-free source of probiotics whenever you need it. After the initial brew, the entire setup will contain enough culture to quickly ferment the freshly brewed tea that's added to top off the kombucha that's drawn out.

Considerations Before Brewing

Volume Of Kombucha To Brew
A continuous system operates the best while brewing considerable amounts of kombucha. The minimum quantity you can consider in such a system is 1 gallon and a maximum of 5 gallons (approx 4 - 22 liters).
Equipment Required For Set Up
Having settled on the volume of kombucha to brew, you can then proceed to pick out the required fermentation container. Ideally, it should be fitted with a spigot for draining out the kombucha.
Check out these articles if you're interested in learning more about Kombucha Bottles and Kombucha Jars and Vessels.
Ingredients Required
It's recommended to get all the components necessary for brewing the tea on hand and have them measured out into the required amounts as per the kombucha recipe.
Sanitize Containers And Equipment
To avoid contamination, all the tools required should be sanitized with hot water or concentrated vinegar. Avoid raw vinegar as it might contain vinegar eels that would infest and render the kombucha undrinkable.

Top Brewing Tips

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Keep Track Of The Ratio Of Starter To Tea
One of the most common factors that lead to unexpected results in brewing is the use of the wrong ratio of starter and sweetened tea. This is because the culture requires a low pH to thrive and also enough sugar to feed on. Mix the starter and fresh sweetened tea in the ratio of 1:8 for the best results.
Type Of SCOBY
Due to the large volume of tea to be fermented in the container, you will require a large SCOBY, preferably 5 to 6 inches across and at least a half to 1 inch thick. Alternatively, you can use several young SCOBYs. If you only have a single young SCOBY you can still use it, but you will have to change the ratio of starter to a much more concentrated rate, preferably 1:3. The first brew will also take much longer.
Shape Of The Container
The shape of the container will influence how fast the brew will be. This is because the yeast culture requires considerable surface area to absorb the nutrients and break them down. The surface area of the fluid surface that's exposed to air should also be large enough to ensure adequate circulation of air whereby oxygen is absorbed, and some of the carbon dioxide escapes.
You Can Feed The SCOBY Other Tea And Sugar Varieties
You are free to blend the type of tea leaves you use to prepare the tea as well as using other alternative sources of sugar such as organic cane juice. As long as the concentration is kept within the required parameters, the brew should ferment just fine and will have a more vibrant aroma and all the accrued health benefits from the tea leaves.
Reduce The Yeast Culture
Controlling the growth rate of the yeast culture helps in reducing the amount of yeast settling at the bottom of the fermentation container. When left to accumulate, it can result in blocking the spigot. One way to deal with this blockage is by using the brush to clean the spigot. A brush is typically supplied with the container.
Keep Track Of The Feeding And Harvesting Schedule
The first brew should take around 14 days; after this, the system will progressively improve, and around the 5th harvest it should have settled to approximately twice per week harvesting. Remember to feed the culture with freshly brewed sweetened tea of similar amount as the harvest.
Controlling The Sugar Content
To control the amount of sugar in the kombucha, you can adjust the brewing schedule to let it ferment for longer. As a result, the culture will feed on most of the sugar. However, do not push it too far, or you will starve the SCOBY, which might also cause the brew to taste sour.
Temperature
The kombucha brewing process is a temperature-sensitive process. Allow the freshly brewed tea to become cool before adding it to the system to avoid denaturing the culture.
Ensure that your container is stored at room temperature (50 degrees F to 75 degrees F or 10 degrees C to 23 degrees C) for optimal brewing results. As a result, the cultures can operate at an optimal environment, ensuring that the brew ferments without loss of quality and taste.
Tea Type
The variety of tea leaves used to brew the tea before fermentation gives the entire batch a unique taste that can only be accomplished by using that specific tea variety.

Equipment Needed

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Equipment Required:
  • 2 gallon glass container with a spigot
  • Tight weave fabric cover
  • Rubber band
  • 2 gallon pot
  • Plastic spatula

Considerations When Buying Brewing Equipment

Metal vs. Non-Metallic
When dealing with kombucha, it's recommended to avoid metallic equipment as the acidic nature of kombucha usually reacts with the metallic surface. It's recommended to use a large glass vessel. The spigot, on the other hand, should be made of food-grade stainless steel instead of plastic to avoid BPA leaching.
Spigot
Some continuous fermentation setups come preinstalled with spigots, thus eliminating the need to set up one manually. Consider getting a high-quality spigot as it's the only moving part and most likely to break over time.
Size Of The Brewing Container
The size should be determined by the amount of kombucha you want to brew. Continuous brewing is best when carried out in containers ranging from 1 to 5 gallons (approx 4 to 22 liters). This makes it much easier to manage the brew and also speed up the fermentation process making it possible to harvest up to 25% of the kombucha every 72 hours.
Cloth Type Used To Cover Container
To keep off dust particles and insects from contaminating the brew, the mouth of the container should be covered with a tightly woven cotton cloth. The cloth can be held into place with a rubber band to keep the opening covered at all times while also allowing oxygen to move into the container while carbon dioxide escapes outwards. 

Ingredients Needed

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Ingredients Required:
  • Freshwater (unchlorinated)
  • Sugar 
  • Loose tea leaves
  • SCOBY
  • Starter tea (previously made kombucha)
See the table below for quantities depending on the amount of kombucha you wish to make:
Amount of Sugar
Amount of Water
Amount of Tea
Amount of Starter
1/2 cup
1/2 gallon
8g
1 cup
1 cup
1 gallon
16g
2 cups
2 cups
2 gallons
32g
4 cups
3 cups
3 gallons
48g
6 cups
4 cups
4 gallons
64g
8 cups
5 cups
5 gallons
80g
10 cups

Considerations When Buying Ingredients

Buy In Bulk
The setup will require frequent feeding, and this calls for freshly brewed tea. Buy the sugar and tea leaves in bulk so that you can keep track of the amount of kombucha you are brewing.
Use Alternative Sources Where Necessary
You can use your favorite tea variety to brew kombucha, and the sugar source can also be changed. Just keep in mind that the replacement must have carbohydrates; otherwise, the SCOBY will starve and wither away. Other sources of sugar include honey, evaporated sugar cane juice, and molasses. If you're interested in learning more about sugar varieties in kombucha, check out our article Kombucha and Sugar here. 
Tea Variety
The type of tea leaves to use during the brewing of kombucha should be considered as it determines the overall flavor of your kombucha. The tea variety will also determine the amount of caffeine left in your kombucha. Ensure that you have enough of the specific type to make the entire batch as per the kombucha recipe instruction amounts.
Brewing Method
To get a better understanding of exactly how continuous fermentation takes place, then we need to breakdown the entire process into setup and brewing processes.

How To Set Up A Continuous Brewing System

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Clean And Disinfect The Equipment
Even if you cleaned your fermentation equipment before storage, it's recommended to rinse them with hot water or concentrated vinegar. This eliminates any harmful bacteria or fungus that might otherwise destabilize the SCOBY culture leading to incomplete brews.
Position The Fermenting Container
To avoid having to struggle around to move the container once it's loaded with the tea, you should position it on a firm surface away from direct sun and at 50 degrees F to 75 degrees F or 10 degrees C to 23 degrees C. Make sure that the spigot is correctly fixed and facing the most accessible direction.

Brewing Instructions:

1. Measure out the required amount of water into a pot and bring to boil.
2. Add tea leaves and sugar and steep it for around 15 minutes.
3. Allow the tea to cool and strain it into the brewing vessel.
4. Mix in the starter tea, use a wooden or plastic spatula to stir the mixture.
5. Place the SCOBYs into the mixture and cover with woven cloth, use a rubber band to hold it in place.
6. Ensure that the container is stored at room temperature and away from direct sunlight for optimum fermentation for the next 14 days.

How To Harvest Kombucha From A Continuous Setup:

1. Prepare a fresh batch of sweet tea, leave it to cool.
2. Place your glass bottle or jar directly below the spigot and gently drain the amount you wish to harvest, it's not advisable to collect more than 25% of the volume each time as it might reduce the culture required to ferment the fresh tea.
3. Top up the system with an equal amount of the fresh tea, allow up to 72hrs of fermentation before the next harvest.

Second Ferment

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The second ferment is purely for flavoring purposes and requires a second fermentation container to ferment the harvested liquid further. This makes it possible to control the final outcome and is highly recommended for anyone who might find raw kombucha too strong.
Kombucha can be flavored with fruits, herbs, spices, or even juices. While these can change the amount of sugar in the kombucha, almost all of it will be used during the second ferment, which usually takes up to 3 days.
Ratio Of Flavors To Use:
  • Almond and vanilla extract: 1/4 tsp per 1 cup of kombucha, if the flavor is a little off adjust accordingly
  • Fruits: 3 cups of fruit extract for every 7 cups of kombucha
  • Juice: 2 cups of juice for every 8 cups of kombucha

How To Set Up A Second Ferment

1. Measure out the flavor into the individual glass bottles according to its ratio and the volume of your containers.
2. Top off the bottles with the freshly harvested kombucha and leave a 2-inch headspace for carbon accumulation.
3. Wipe clean the mouth of the bottles before tightly screwing on the lid.
4. Leave to ferment at room temperature for three days, after which the bottles can be moved to the fridge where the fermentation will proceed at a much slower rate due to the reduced temperatures. As the temperatures fall, the yeast and bacteria cells go dormant as their metabolic enzymes get deactivated. The bottles can last up to 2 weeks in the fridge unopened, once open they should be consumed within three days.

Troubleshooting Your Kombucha Brew

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My Continuous Brew Has Become Too Sour
This is usually caused by delays in harvesting, thus leading to extended fermentation and an increase in acetic acid. To reduce the sourness, harvest up to 35% of the kombucha and top up with freshly brewed sweet tea. The sour-tasting kombucha can then be flavored via a second ferment.
My Brew Is Taking Too Long
If it's your first brew after setting up the system, then that's normal as the culture can get overwhelmed for the first week before it gradually feeds on the rest of the sugar. However, if the brew takes longer than 18 days, then you should add another new SCOBY to increase the number of bacteria and yeast.
Mold Has Grown On The Top Layer
The presence of mold indicates that the symbiotic balance between the yeast and bacteria is no longer maintained, which has allowed the growth of mold. As a result, the entire batch is deemed contaminated and should, therefore, be disposed of, and the tools cleaned up before fermenting again.
When Should I Clean The Vessel?
While it doesn't require frequent cleanups, it's necessary to perform a complete cleanup at least twice or thrice per year, this makes it possible to remove the excess yeast that accumulates at the bottom and unblock the spigot.

How To Clean A Continuous Brewing Setup:

1. Remove the SCOBY
Gently take out the SCOBY from the vessel and place it in a SCOBY hotel. If you want to learn more about how to store SCOBY, check out our article SCOBY Hotel here. 
2. Empty the kombucha into a large glass container
So as not to upset the layers of yeast residue at the bottom, place the second glass container on a lower surface and release the spigot, this should empty most of the liquid. The remaining sediments at the bottom should be disposed of.
3. Wash the container with soap.
The container should then be washed thoroughly with soapy water, avoid using antibacterial soap as it might compromise the health of the culture. Rinse thoroughly with cold water. A second rinse using concentrated vinegar is also recommended. 

SCOBY Care

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Trim The SCOBY
The SCOBY used is more likely to grow and expand due to the ever present nutrients to feed on, thus taking too much space, which could otherwise be occupied by kombucha in the vessel. For this reason, you can cut it into halves and store the additional SCOBY in a SCOBY hotel.
Rotate SCOBYs
After taking apart your setup for cleaning, it's recommended to switch the SCOBY if you have multiple ones. This allows the SCOBY to regain its health to prevent it from turning dark too early.
Keep The SOCBY Well-Fed When It's Not Being Used To Brew
Even during storage the culture will still need nutrients to feed on. Remember to add some freshly brewed sweet tea to the hotel when you add the SCOBY.

FAQs

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What is continuous brewing?
This is a method of brewing kombucha that allows for harvesting up to a quarter of the product, which is replaced with fresh tea to keep the cycle going for up to 6 months.
Can you ferment kombucha too long?
Technically no. However, when left to ferment for too long, the pH usually drops below 2.5, making it sour and taste like vinegar, and therefore, it will be unpleasant to drink, but not necessarily unsafe. The FDA recommends kombucha should be between 4.2 to 2.5 pH.
Why is metal bad for kombucha?
Due to its acidic nature, kombucha tends to react with most metals leading to contamination. If you must use metallic tools when dealing with kombucha, ensure that they are at least made of stainless steel.
Can I put 2 SCOBYs in my kombucha?
Yes, it's all the same if you use a single or 2 SCOBYs; as long as you mix the tea and starter tea in the right ratio, you can use any number of SCOBYs you want.
How do I make my kombucha fizzy?
To make your kombucha fizzy, you should use a sugar-rich flavor such as fruits during the second ferment. The extra sugar gets broken down by the culture during fermentation, and the carbon dioxide produced makes the drink turn fizzy.

 

 

Interested in learning more about kombucha?
Check out these articles:
Kombucha and pH
Kombucha Bottles
Does Kombucha Go Bad?
How to Pronounce Kombucha
How Much Caffeine Is In Kombucha?
Vinegar Eels
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