Kombucha FAQ’s
Mastering the Craft of the SCOBY: Your Comprehensive Kombucha Brewing Guide
Welcome to Ireland’s most trusted Kombucha resource, where we have helped over 5,000 home brewers master the art of making kombucha. Whether you are troubleshooting your first SCOBY or looking to achieve that elusive second fermentation fizz, this guide provides the expert-led clarity you need. Move beyond the basics and learn how to balance acidity, tea tannins, and sugar to craft a sophisticated, small batch probiotic tonic at home.
We understand that starting your first batch can feel like a science experiment. ‘Is that brown stringy bit normal?‘ ‘Is my SCOBY supposed to sink to the bottom?‘ These are the most common questions we hear from our community of over 5,000 Irish home brewers. This guide is designed to move beyond basic instructions and provide you with the deep troubleshooting expertise required to maintain peak culture vitality and achieve the perfect balance of organic acids.
The 4 Pillars of Success
1. The Nutrient Foundation: Tea & Sugar Selection
The most frequent cause of a “weak” or “sluggish” SCOBY is nutrient deficiency. Unlike other ferments, Kombucha requires Nitrogen, Tannins, and Caffeine found in real tea (Camellia sinensis). We recommend Organic Black or Green tea and Organic Cane Sugar. Avoid herbal teas or essential oils (like Earl Grey), as these can act as anti-bacterials that “starve” or weaken your culture over time. The sugar isn’t for you, it’s the fuel the SCOBY needs to transform tea into a complex probiotic tonic.
2. The Acid Guard: Starter Liquid & pH Balance
In Kombucha brewing, the liquid is just as important as the SCOBY itself. Your Starter Liquid (highly acidic kombucha from a previous batch) is your defense mechanism. It drops the pH of your fresh tea immediately, creating an environment where “good” bacteria thrive and “bad” mold cannot survive. For a safe and successful ferment, your brew should always start at a pH of 4.5 or lower and finish between 2.5 and 3.5.
3. Oxygen & Airflow: The Breath of Life
Unlike Water Kefir, which is often fermented with a loose lid, Kombucha is aerobic, the SCOBY needs to breathe. The bacteria in the culture use oxygen to convert ethanol into healthy acetic acids. We recommend using a tightly woven cloth cover (like a muslin) secured with a band. This allows oxygen to flow while keeping out fruit flies and contaminants. Never seal your jar with a solid lid during the first fermentation, or you will “suffocate” the SCOBY and stall the process.
4. The Heirloom Promise: The Ever-Growing SCOBY
The beauty of a NutriBrew SCOBY is its Self-Replicating nature. Every batch you brew will naturally grow a “daughter” SCOBY on the surface, meaning your culture literally renews itself with every cycle. Unlike lab grown powders, this is an Heirloom Legacy. With proper care, consistent feeding, and a warm Irish kitchen, your initial culture will provide an infinite supply of probiotics, allowing you to share “starter kits” with friends and family for years to come.
Ready to start your own brew?
Shop Fresh Kombucha SCOBYs →SCOBY Health & Troubleshooting
No, this is perfectly normal. While most SCOBYs (Symbiotic Culture of Bacteria and Yeast) float, they can sink or hang sideways due to temperature changes or density. A new pellicle (baby SCOBY) will usually begin to form as a thin, translucent film on the surface regardless of where the original “mother” sits.
Those “brown stringy bits” are actually yeast colonies. They are a sign of a healthy, active fermentation. You can leave them in, or if you prefer a clearer brew, you can strain them out when bottling.
SCOBY growth is driven by temperature and surface area. In the cool Irish climate, it can take 7–10 days to see a visible layer. Ensure your jar is in a spot that stays between 20°C and 26°C. If your tea is too cold, the bacteria cannot produce the cellulose needed to build the SCOBY.
If you see fuzzy, dry spots that are green, white, or black, toss the entire batch. Mold is rare but dangerous. It usually occurs if the starter tea wasn’t acidic enough or the environment was too cold. Thoroughly sterilize your jar with vinegar and start over with a fresh NutriBrew SCOBY and starter liquid.
In the Irish climate, this is often a “yeast-imbalance” caused by cool temperatures. While the bacteria are producing acids (vinegar smell), the yeast—responsible for bubbles—may be sluggish. To fix this, ensure you are stirring your starter liquid before adding it to a new batch to distribute the yeast evenly, and try to maintain a consistent 23°C. If the first fermentation is too cold, the yeast won’t produce enough CO2 for the second fermentation.
A SCOBY is a biological filter, and holes usually form due to oxygen bubbles trying to escape from beneath the pellicle. As the yeast produces gas, it pushes upward; if the SCOBY is thin, it “tears” slightly to let the gas out. It’s a sign of active carbon dioxide production. As your brew matures, these holes will usually fill in with new layers of cellulose.
This is perfectly safe. That sediment is simply dormant yeast that has settled out of the liquid after carbonation. It is a sign of a “living” drink. You can gently swirl the bottle before opening to incorporate it (for extra B-vitamins) or leave the last 10ml in the bottle if you prefer a clearer pour.
This is usually caused by an overgrowth of a specific bacterium (Pediococcus) often triggered by using too much sugar or brewing at very high temperatures. While not harmful, the texture is unpleasant. To reset, use a bit less sugar in your next batch, ensure your brewing vessel is thoroughly cleaned, and try to keep the temperature around 23°C.
Precision Ratios & Ingredients
For peak grain vitality, use Organic Black or Green tea (Camellia sinensis). Avoid flavored teas like Earl Grey, as the essential oils (bergamot) can weaken the SCOBY. For sugar, Organic Cane Sugar is the gold standard; it provides the most accessible food source for the yeast to transform into beneficial acids.
pH strips are the “GPS” of fermentation. They take the guesswork out of safety. Your finished kombucha should ideally be between 2.5 and 3.5 pH. Using strips ensures your brew is acidic enough to prevent mold growth and safe for consumption.
No. Like a sourdough starter, every SCOBY has a unique microbial thumbprint based on the tea it was raised in. NutriBrew SCOBYs are “Heirloom” cultures, meaning they are lab-tested for probiotic diversity and designed to be self-replicating for a lifetime.
Most Irish municipal water contains chlorine or chloramines to keep it “safe,” but these chemicals can weaken your SCOBY over time. If you don’t have a water filter, you can boil your tap water for 15 minutes and let it cool completely, or leave it in an open pot overnight. This allows the chlorine to evaporate, ensuring your microbes stay vigorous and healthy.
Yes, but do it immediately. The starter liquid’s primary job is to lower the pH of your sweet tea to below 4.5 to prevent mold. If your tea has been sitting “unprotected” at room temperature for more than a day, check for any off-smells first. If it smells fresh, add the starter liquid now. In the future, always add it at the start to ensure the “acid safety net” is in place.
The Fermentation Cycle
The “Straw Test” is your best tool. After 7 days, insert a straw below the SCOBY and taste. It should be a balance of tart and sweet. If it’s too sweet, let it ferment longer. If it’s too vinegary, use a shorter cycle next time.
Kombucha loves a “Goldilocks” range of 20°C to 26°C. If your Irish kitchen drops below 20°C, the fermentation will stall, and the risk of mold increases. We recommend a warm cupboard or a seedling heat mat during winter months.
Yes! With every batch, a new “daughter” SCOBY forms on the surface. You can stack these (creating a “SCOBY Hotel”), share them with friends, or compost the older, darker layers to make room for fresh growth.
Safety is paramount. Always use “flip-top” bottles designed for pressure (like Grolsch-style bottles). To prevent excessive pressure, “burp” your bottles once a day during the second fermentation to check carbonation levels. Once you hear a healthy “hiss,” move them to the fridge immediately. The cold temperature stops the yeast from producing more gas.
Maintenance & Storage
Kombucha SCOBYs are infinitely reusable. To take a break, create a “SCOBY Hotel“: Place your SCOBYs in a jar with plenty of fresh sweet tea and store it at room temperature (not the fridge) for up to 6 weeks. It will simply become very acidic, acting as a potent “starter liquid” for your return
Once bottled and carbonated, kombucha will stay fresh in the fridge for 4–6 weeks. The cold temperature puts the culture into a “dormant” state, preserving the flavor profile and preventing it from turning into vinegar.
We strongly advise against this. Placing a SCOBY in the fridge puts the bacteria into a deep dormancy, but the yeast often stays somewhat active. This imbalance makes the culture highly susceptible to mold when you try to “wake it up” later. For breaks up to 6 weeks, simply leave it in a fresh batch of sweet tea at room temperature. It will be fine.
A SCOBY Hotel is simply a separate jar filled with strong starter liquid where you store your spare cultures. As you brew more batches, you’ll have extra SCOBYs. Keeping a “Hotel” acts as a backup in case a batch gets moldy, and it provides you with a source of extremely potent starter liquid (Kombucha Vinegar) for future brews.
Mastering the Craft of Living Cultures
You are now part of a centuries old tradition of home fermentation. Because a Kombucha SCOBY is a complex, oxygen breathing ecosystem, it may take a few cycles to fully ‘acclimatize’ and develop its signature tartness in your home environment.
We encourage you to use our protocols as your foundation, but as you gain confidence, don’t be afraid to experiment with tea blends and artisanal fruit infusions. Over time, you will develop a crisp, sophisticated probiotic tonic that is uniquely yours. Should you ever have a question or need a troubleshooting tip, Ireland’s most dedicated community of brewers is right here to help.