Temperature & Time
Q: I'm not sure if the temperature gauge is working. Why is it not showing any readings?
A: If your temperature gauge isn't showing any readings, it's very likely that the temperature of the liquid is falling somewhere outside of 58-88 degrees, so it can't read it. (Typically, this happens when mixing in the warm sweet tea and the liquid is still above 88 degrees)
If the temp gauge is reading 2 or 3 colors, this means the actual exact temperature is lying somewhere in between the numbers on the gauge. Green indicates the correct temp. If green is not visible, the temperature will be midway between what is illuminated by tan and blue.
Q: How can I keep my brew warm if my house is cold?
We are located in Madison, WI so we're experts at brewing in cold temps! Here are some of our top tips for keeping your brew warm:
1) In the winter, we prefer to move our jars up to a high shelf in a warm room, like on top of cupboards or a tall bookshelf. Sometimes this means moving the brew jar upstairs, where it tends to be warmer (if you have a multi-story home).
2) If your brew jar is resting on a cold countertop, place a book or cutting board underneath it for insulation.
3) If taking those steps doesn't get the temperature above 68 degrees, we do recommend using a heating pad—setting it on its lowest setting, and wrapping it around the jar. This can be very effective at maintaining a consistent temperature in the mid 70's.
The trick with using a heating pad is checking on it so that it doesn't get too warm. Our brewing kits come with a temperature gauge to make it easy to always read the temperature on the side of the jar. If the heating pad starts overheating your brew (in the mid to upper 80's is too warm) then only use the heating pad for a few hours a day. Once you flip off the heating pad, you can keep a towel wrapped around the jar to retain some of that heat for a few hours.
As for the second fermentation, it is less necessary to keep the temperature in the 70's. Simply store your kombucha bottles somewhere they will stay above 68 degrees. If you want to move the second ferment along quicker, then store them somewhere warmer.
Q: What is the importance of temperature when brewing?
A: It's important to keep your brew jar as close to 74-76 degrees as possible, that is when the culture produces the most balanced ratio of yeast to bacteria. As you'll soon discover, kombucha brewing is all about finding balance.
It's fine if your brew drops as low as 68 degrees. However, if it goes below 68 degrees for an extended period of time it can be more prone to develop mold, as the bacteria and yeasts will start to go to sleep. The colder it is, the longer it will take to brew. And vice versa, the warmer it is, the faster it brews.
If your home is very warm in the summer, it's important to keep your brew jars somewhere cooler so they won't get too hot. It's best to not let your brewing jars stay above 84 degrees for too long or your yeasts will begin to overpopulate and throw your brew out of whack.
Q: My temperature gauge has several different colors on it. Which color indicates the actual temp of the brew?
A: If the temperature gauge reads 2 or 3 colors, it means the exact temperature is lying somewhere in between the numbers on the gauge. Green indicates the correct temp. If green is not visible, the temp will be midway between what is illuminated by tan and blue.
Q: My brew has been sitting for over a week. I tested the pH per the directions and the reading was too high. What do I need to do to get the pH to the recommended 2.5 to 3.5?
A: The slow growth/fermentation could be due to a low temperature. If you are brewing at the lower end of average (70/72 degrees), let it brew for another 5-7 days and then give it another taste test and pH test and see how everything looks! Brewing at a lower temperature will work fine, it just might take a little longer.
Q: How hot is too hot for a kombucha culture?
A: A culture can hit 95-100 degrees for a short time and survive just fine (like during shipping). Optimally, you want to be able to keep it consistently in the mid 70's, or upper 70's at the most. If the temperature goes above 88 for more than a few hours, the bacteria get out of control and throw off the brew. That is why our temperature gauge stops reading above 88—because the temperature really shouldn't ever be any higher than that.
Q: Can I store my culture in the refrigerator?
A: You can store kombucha cultures in the refrigerator for a short period of time; roughly 2 weeks is all we recommend. Storing in the refrigerator is a risk—the yeasts and bacteria go dormant in the cold temperatures and can have a hard time bouncing back to full brewing strength after they have been chilled. Sleepy yeast and bacteria leave your brew more at risk for developing mold.
If you do refrigerate your culture, store it in a glass jar in at least 1 to 2 cups of starter tea with a lid. The night before you would like to brew again, simply remove it from the refrigerator, place on your countertop and cover with a cotton cloth and rubber band. Allow the culture to return to room temperature overnight before brewing the next day. If it has been refrigerated for a period longer than 2 weeks, feed your culture the night before brewing with it. (To feed your culture, make one cup of hot caffeinated tea, and dissolve 1/3 cup of sugar in the tea. Allow the sweet tea to cool to room temperature and add it to the jar housing your culture & starter tea. Repeat this process every 4 weeks to ensure the health of your culture.)
Q: I have been brewing for a few days and my culture suddenly sank to the bottom of the jar. Is that okay?
A. Yes! That is fine. There was likely a fluctuation in temperature and it caused the culture to sink. It can sink, it can float on top or sit in the middle—it's fermenting all the same. Your culture is still working hard to produce a new culture that will cover the surface of your brew. Evidence of this new culture should appear by Day 7. It can take up to 2 weeks for a new culture to grow in on the top.
Q: Can I brew my kombucha for more than 3 weeks?
A: It entirely depends on the temperature. If you can leave the brew jar in a cool location (74 degree or lower) then 3 weeks is totally fine. It will undoubtedly be tart, but you can simply sweeten it back up with sugar/ fruit during the second fermentation.
When you then do the second ferment, we recommend going no more than 3 to 5 days. If your bottles are stored in a warm location, try to keep it closer to 3 to avoid too much carbonation.
Q: I'm on Day 7 of brewing and my new scoby is pretty thin. Is this normal?
A: For Day 7 at 75 degrees, we would expect a culture to be about a quarter of an inch thick. However, the majority of scoby growth tends to happen between Days 7-21, so no need to worry just yet. Make sure that the culture is in the proper temperature range (68-84 degrees), as being too cold or hot can inhibit scoby growth.
Also, keep in mind that the first time brewing with the kit is usually the slowest. After a couple of brews, the culture and starter tea begin to establish themselves and fermentation happens faster.
If, after a few more brews, your culture isn't growing in well, or your kombucha tastes off, then you may need a new culture/starter tea pouch. Certainly keep and set aside your current culture and starter tea for future use (at the very least you can get two batches going simultaneously) but with a new starter tea/culture pouch you will be able to determine if the culture/starter tea is the problem, or if something else is amiss.
Q: How do you test the pH with the culture in the jar?
A: To test the pH with the culture in the jar, you can slide the strip down along the side of the jar, or just lift/push the culture out of the way to dip test.
Q: My first batch has been brewing for ten days and it tasted good to me. I started filling my bottles when I realized I had not tested the pH. Will this be harmful to drink?
A: It shouldn't be harmful to drink. If your kombucha looks, smells and tastes good, then it is good. Our tongues are our most useful instrument when brewing kombucha; pH strips are provided as a teaching tool and a "just in case" measure for those folks wanting a little added reassurance.
Q: Why can't I move my brew jar once I've started to brew it?
A: In the first 7 days of brewing, your culture is processing the tea and sugar and beginning to grow the new culture on top. Moving it disrupts this process and makes it hard to grow the new culture. Once the new culture has formed, you can gently move the jar should you wish. Don't panic if you moved your jar around during the first 24 hours. Just try not to bump or move it during days 2-7.
Q: How do I store the culture when I want to take a break in between brews?
A: We recommend storing it on your countertop, in a glass jar (the 1 gallon brew jar works well), placed in at least 1 to 2 cups of liquid kombucha starter tea (your previously brewed kombucha) and covered with the cotton cloth and rubber band. You can store it like this for up to 4 weeks, at which point it will likely need to be fed. To feed your culture, make one cup of hot caffeinated tea, dissolve 1/3 cup of sugar in the tea. Allow the sweet tea to cool to room temperature and add it to the jar housing your culture and starter tea. Repeat this process every 4 weeks to ensure the health of your culture.
Q: My culture has a bunch of bubbles on the top of it. Is that ok?
A: Yes, air bubbles are caused by a change in air temperature or air flow. It's totally normal to see some bubbles.
Q: How long can I leave the culture in its plastic bag before brewing?
A: We recommend brewing within 2 to 3 weeks of arrival, as the sooner you brew, the fresher the culture is and the better your kombucha will be. However, our culture pouches are shelf stable at room temperature for 3 months. If you do plan to store the culture in its pouch for an extended period of time before brewing, we recommend doing so in a cooler pantry at, or under, 70 degrees.