Fruit Fly Trap

Fruit flies can be quite troublesome for kombucha brewers, particularly during the warmer months. To help prevent fruit flies from getting into your brew, it is suggested to cover your ferment with a breathable covering with tight weaving. If you do use cheesecloth, layering the cheesecloth with multiple layers is also recommended.

Brewing

Making a fruit fly trap is an effective and easy way to catch fruit flies. To make a fruit fly trap, take a glass jar, and add some kombucha or apple cider vinegar (or any vinegar other than white vinegar) to the bottom with a few drops of liquid soap. Placing an inverted funnel in the glass jar (such as the top half of a plastic water bottle) also helps to ensure that the fruit flies won't escape.

Fruit fly trap

Read some more about kombucha and fruit flies and other kombucha cautions and concerns on Happy Herbalist.

Q&A: I left my kombucha mushroom in the fridge for awhile. Can I still use it?

I've been receiving many questions about individuals who have SCOBYs stored in the fridge, or brews forgotten on the counter. Can you still use the SCOBY to brew?

I typically say yes, but it also depends on various factors.

Usually I recommend to individuals that SCOBYs can be stored in the refrigerator for up to a year, with increased chances of the SCOBY remaining viable the better your sanitation is. In addition, I usually do not recommend individuals to leave their brews out for more than a few weeks, but this is also dependent on several factors (for example, fermentation goes slower at cooler temperatures). If you do leave your brew forgotten on the counter, it's still possible that you can use your kombucha mushroom.

Typically, kombucha smells like hard cider or apple cider vinegar. The longer the kombucha and the mushroom are stored, the more acidic the kombucha will be in taste and smell. Here are some suggestions for what to do if your kombucha is too sour.

If you notice anything funky, such as mold, or off-odors, it may be safer to just discard your kombucha mushroom in the compost. If this is the case, you may consider growing a kombucha mushroom or finding other sources for a SCOBY.

However, if you don't find anything out of the ordinary, you may just want to give brewing with the mushroom a try! If you have some fresher starter tea to use as well, that can also be helpful.

If a SCOBY has remained dormant in the fridge for awhile, it may take a few cycles for the mushroom to kick back into gear. And if your intention is to grow a nice thick mushroom (because brewing good-tasting kombucha and growing a thick SCOBY do not always equate to the same thing), you may consider reading this post for tips. Once you have a good younger mushroom to brew with (or a few), you may want to put the older SCOBY to rest in the compost. In my experience, the younger mushrooms tend to out-perform the older ones.

Unsure if your brew or mushroom are safe? Read Happy Herbalist's Kombucha Cautions and Safe Brewing Tips. Some pictures of healthy mushrooms can be found in this post, and pictures of healthy (and unhealthy) mushrooms can be found on Happy Herbalist's Kombucha Pictures page.

Happy brewing!

Q&A: Kombucha SCOBYs vs. Mothers of Vinegar (MOVs)

Q: If I've grown a kombucha SCOBY or brewed kombucha using unpasteurized vinegar as a starter, do I have a kombucha SCOBY or a mother of vinegar?

A: Today's post is dedicated to kombucha SCOBYs and mothers of vinegar (MOVs). Because of their similar appearance and function, sometimes one can be confused for the other. And if you've grown a kombucha SCOBY or brewed kombucha using unpasteurized vinegar as a starter, do you have a kombucha SCOBY or a MOV? The goal of this post is to address this question and to clear up some of the confusion behind the similarities and differences between these two cultures.

Kombucha SCOBYs are used to ferment a sweet tea solution to make kombucha, and the term "SCOBY" stands for symbiotic culture of bacteria and yeasts. The exact composition of a kombucha SCOBY varies, but here is a sample analysis of a kombucha ferment and a certified analysis of a Happy Herbalist kombucha mushroom. According to Happy Herbalist, the three universal elements in all kombucha mushroom strains are gluconic acid, acetic acid, and fructose.

Meanwhile, mother of vinegars (MOVs) are used to produce vinegar. MOVs are cellulose substances made of strains of Acetobacter (1, 2) and bacteria that produce acetic acid.

Kombucha SCOBYs and MOV's look strikingly similar:

Kombucha SCOBY

Mother of VinegarPhoto source

The similar appearance of Kombucha SCOBYs and MOVs are due to the presence of Acetobacter strains, which synthesize the cellulose structure of both organisms.

According to Happy Herbalist, the difference between kombucha and vinegar is that kombucha has gluconic acid, while vinegar does not.

In addition, according to a study cited in the Cornell study, Acetobacter xylinum converts glucose to gluconic acid in kombucha. In kombucha, glucose commonly comes from sucrose (such as table sugar or evaporated cane juice), which is made up of glucose and fructose. From my research on the internet, it appears that Acetobacter xylinum is a strain that can also be found in MOVs. Additionally, I believe that some vinegars (such as apple cider vinegar) do not contain glucose or gluconic acid because they are made of fruit sugars, which are purely fructose.

Traditionally, if you are brewing kombucha for the first time, and you only have a kombucha SCOBY and no starter tea for your brew, one recommendation is to add a little bit of distilled white vinegar to the brew to help bring the pH down. This can help to prevent spoilage microorganisms from growing in the brew, while encouraging the kombucha strains to proliferate. It is traditionally not recommended to introduce unpasteurized or raw vinegars to your kombucha, which could encourage the vinegar strains and produce a mother of vinegar (3, 4).

Some people are concerned that their kombucha SCOBYs may be MOVs if they used raw unpasteurized vinegar as a starter to grow a kombucha SCOBY or to brew kombucha. First off, I would like to say that I am not a vinegar or MOV expert. However, I believe that even if you grow a kombucha SCOBY using the same method that I used to grow a kombucha mother (except for using raw vinegar as a starter instead of kombucha), and if you are feeding the culture glucose, fructose, and tea, and brewing as how you would traditionally brew kombucha, you should be getting benefits from the beneficial acids produced in the brewing process. Just like kombucha, there are health benefits associated with the consumption of unpasteurized vinegars. My hypothesis is that feeding such a culture grown from raw vinegar could still create a SCOBY, because it seems that there are some similar strains in kombucha SCOBYs and MOVs, and natural yeasts and bacteria in the air would be incorporated in the culture to create a SCOBY, as well. I have tried someone's kombucha before, which was brewed from a kombucha SCOBY originally grown from raw apple cider vinegar, and the kombucha tasted similar enough to me that I would have called it kombucha.

It appears that what truly defines what is kombucha (or if you might not have kombucha) depends on your definition. Again, according to Happy Herbalist, the difference between kombucha and vinegar is that kombucha has gluconic acid, while vinegar does not. Meanwhile, according to the Steve Dickman, the co-founder of High Country Kombucha, what makes their kombucha "authentic" is the presence of the strain Z. Kombuchaensis in their brew (see this video, at around time 1:00).

Similar to yogurt, kombucha strains vary considerably, depending on the environment the kombucha is brewed in (because there are different yeasts and bacteria in the air), the ingredients used, and more. For example, High Country Kombucha lists Gluconacetobacter Obediens, Dekkera Anomala, Dekkera Bruxellensis, and Z. Kombuchaensis on their bottle as probiotics present in their kombucha. Meanwhile, GT's Kombucha bottle lists Lactobacillus bacterium and S. Boulardii as probiotics and glucuronic acid, lactic acid, and acetic acid as organic acids present in their kombucha.

Unless you have a kombucha company or if you are an individual looking for specific benefits related to specific strains and specific acids in kombucha, most people will still benefit from the beneficial acids produced in kombucha even without knowing the exact strains that the brew contains, and whether the kombucha was brewed from a batch made with raw vinegar or kombucha as a starter.

Ideally, if you can get a kombucha SCOBY and kombucha as starter tea when you begin to brew, I would use that. If you only have one or the other, and if you want to be more assured of making purely kombucha strains, I wouldn't add unpasteurized vinegars. But, I wouldn't rule out using unpasteurized vinegar as a starter for your first brew, if you can't get access to raw kombucha as a starter. In addition, you will only need vinegar for the first time that you brew, because after your first batch, you will be using the kombucha from your last batch as starter tea. However, what you choose to use will depend on your situation and what you would like to incorporate in your kombucha.

The only way to be truly assured of exactly what is in your kombucha is to get your kombucha and SCOBY tested in a lab. And I do admit, I would be very interested in testing my home-brewed kombucha to find out exactly what is in there! However, although there are specific health benefits associated with specific strains of probiotics, I believe that most people can benefit from the live cultures present in kombucha, whether they know exactly which strains are in it or not.

This is my understanding of kombucha SCOBYs and MOVs at the moment. If anyone has any additional comments, thoughts, or knowledge on the matter, please share!

P.S. If you are interested in learning more about vinegar and how to make wine vinegar, I really enjoyed this thorough blog post and photos.

Happy brewing!

A Word On: Mold

I have been lucky in that I have never encountered mold when brewing kombucha.

Kombucha has been found to have a low rate of contamination and of mold, and has been found to be safely prepared at home (1). Kombucha's low risk of contamination results from its natural anti-microbial activity, attributed largely to the presence of acetic acid according to the Cornell study (1). Kombucha's low pH also helps to prevent undesired microorganisms from proliferating.

Remember that kombucha mushrooms come in all shapes, sizes, and colors, and colors can range from creamy white to all variations of brown. And if you've never seen the development of a SCOBY completely from scratch, look at my photos from Experiment 1, Growing Your Own Kombucha Mother.

If you do suspect mold, remember that it should appear FUZZY such as the mold you see on bread.

Photos from Happy Herbalist

If your kombucha mushroom does form mold, the safest thing to do would be to throw out that batch and that mushroom, and to brew with another mushroom- another great reason to have a backup mushroom in storage. I've talked to several people who have cut off the mold-infected part of the mushroom and continued to use the rest of the SCOBY, but do this at your own discretion! If imperceptible mold spores are in the rest of the mushroom or in the brew, this could cause problems for the next batch, so you may want to start anew!

Photos from Organic-Kombucha.com

More info on mold can be found in Happy Herbalist's Brewing Guide and Kombucha Photos page.

Reference
1. Greenwalt, C.J., R.A. Ledford, and K.H. Steinkraus. "Determination and characterization of the anti-microbial activity of the fermented tea Kombucha." Lebensmittel-Wissenschaft und-Technologie 31 (3) (1998): 291-296.
-Online article link here.

Q&A: Why does my kombucha smell like sulfur and/or rotten eggs? Is it safe to drink?

Q: Why does my kombucha smell like sulfur and/or rotten eggs? Is it safe to drink?

A: A rotten egg smell comes from sulfur. The presence of sulfur may be:

• A product of nitrogen from the tea
• From the water source
• Another thread to read on kombucha and sulfur can be found here

Because kombucha and beer are both products of fermentation, the reasons for sulfur/rotten egg smells in beer may be the same for kombucha:

• According to beer brewing sites, sulfur smells in beer may be due to byproducts of certain yeasts, yeast autolysis (yeast cannibalism), or bacterial infection
• The sulfur smell goes away in beer over time according to this thread and FAQ 5.43.

Is the kombucha safe to drink?
According to the threads here and here, it appears that the kombucha is still safe to drink even if it smells like sulfur/rotten eggs. However, if you don't feel good after you drink it, stop!

What can you do?

• If you think the sulfur smells are due to your water source, consider using a water filter or upgrading your current water filter.
• Let your kombucha age for longer periods of time before you drink it to see if the sulfur smells decrease over time.
• If you think the sulfur smells are due to certain yeasts in your kombucha, try favoring the bacteria in your brew.
• Try cleaning all of your equipment and make sure you practice proper sanitation techniques.
• Try starting over with a new SCOBY.

If you have had any experiences with your kombucha smelling like sulfur and/or rotten eggs, have any other suggested solutions, or have any success stories, feel free to share!

Q&A: When is my kombucha done fermenting? (Updated 5-31-2010)

Q: How do you know when your kombucha is ready to drink, ready to bottle, or if it's done fermenting?

A: If you are brewing using the traditional method, your kombucha may be done at anywhere between 6-14 days. The time may even be more or less, depending on personal preference, the amount and strength of the starter tea you used, and various environmental factors, such as temperature. So how do you know when your kombucha is done? Here is a list of several signs that help to indicate when your kombucha is ready (please note that not all of these need to apply!):

• According to taste- the most important indicator, as individuals have varying preferences for the amount of fizz, the strength of the sweetness, and the intensity of the vinegar-taste of kombucha
• Hard apple cider or apple cider vinegar aroma or taste present
• The kombucha tastes slightly sour or acidic (like vinegar)
• Kombucha gets more cloudy/opaue, and thus becomes lighter in color, the longer it ferments due to yeast reproduction
• The partial/complete formation of a new kombucha baby
• Kombucha is bottled "optimally" at a pH of 2.5 - 3.5 (testing pH is optional)

Note the clearness of the kombucha at the beginning of fermentation (left) and the cloudiness of the kombucha at the end of the primary fermentation process (right). (My apologies if it is hard to tell in this photo).

Note:

• Home-brewed kombucha tastes a lot different than GT's traditional kombucha. I've found that Katalyst and High Country kombucha taste more similar to home-brews.

Q&A: How do you grow a thick kombucha mushroom?

Q: How do you grow a thick kombucha mushroom?

A: Remember that Kombucha Mushrooms Come in All Shapes, Sizes, and Colors! Even if your kombucha mother does not look like a perfectly even 1/8 - 1/2 inch thick cream-colored pancake, it could still ferment your kombucha very well!

If you want a thick kombucha mother, you can put some kombucha in a clean glass jar, cover it well with a breathable cloth, and let it sit for a few weeks until a thick mother grows and develops. Or, you can just let one of your kombucha brews ferment for a prolonged period of time until a thick SCOBY forms.

The kombucha will become pretty strong, sour, and acidic if it has been fermenting for a long time, and using this kombucha as starter tea will favor the bacteria and thick SCOBY formation (1). For other uses of sour kombucha, check out Happy Herbalist's recommendations: Kombucha Tea Too Sour?

Acetobacter xylinum has been indicated to be one of the main bacteria in the colony that helps to form the cellulose structure of the kombucha mushroom (2-3). So to favor a thick kombucha mother, you want to favor the bacteria.

For more information on decreasing yeast to bacteria ratios, which will favor the bacteria and a thick SCOBY, visit Kombucha Balance: Decreasing the Ratio of Yeast to Acetobacter Populations.

References:
1. Kombucha Balance: Decreasing the Ratio of Yeast to Acetobacter Populations2. Greenwalt, C.J., R.A. Ledford, and K.H. Steinkraus. "Determination and characterization of the anti-microbial activity of the fermented tea Kombucha." Lebensmittel-Wissenschaft und-Technologie 31 (3) (1998): 291-296.3. Malbasa, R., E. Loncar, and M. Djuric. "Comparison of the products of Kombucha fermentation on sucrose and molasses." Food Chemistry. 106 (2008): 1039-1045.

Q&A: Can you brew kombucha with honey?

Q: Can you brew kombucha with honey?

A: Some people swear that brewing with honey works, while others say that brewing with honey doesn't work because of honey's anti-bacterial properties.

Everyone pretty much agrees that brewing with cane sugar works. However, health benefits of other sweeteners often come up as an issue. In addition, taste is another aspect you may want to consider.

Although I have never personally brewed with honey, something to remember is that if you introduce something foreign to the kombucha culture, even if you don't see any immediate short-term effects on the culture, there may be unforeseen long-term effects.

For example, the SCOBY will not survive in the long-term if you brew kombucha using only herbal teas, such as rooibos. However, if you brew kombucha with an herbal tea for only one or two weeks, the culture will most likely survive. Thus, some individuals alternate brewing herbal and non-herbal brews, or brew with a combination of herbal and non-herbal teas. (Read more on brewing with herbal teas at The Different Teas for Your Kombucha Brew).

If you're interested in brewing with honey, I would recommend having a back-up mushroom, such as by storing a spare SCOBY in kombucha made with cane sugar in the fridge.

More on Kombucha and Honey:

• From Gunther Frank: Kombucha Tea: What's All the Hoopla? (around two-thirds down the page, "Can honey be used instead of sugar?")
• Steve Dickman, the co-founder of High Country Kombucha, states that brewing kombucha with honey works in this video (he begins talking about kombucha and honey at time 7:18)
• It's possible according to Happy Herbalist

No SCOBY

Where is that baby mushroom? If you've been brewing kombucha/have been trying to and haven't been getting any new kombucha mothers, here are some tips:

• If your SCOBY was previously stored in the fridge: kombucha mushrooms go dormant in the fridge and may need a few cycles to get fully back into gear. Wait a few cycles to see if new SCOBYs begin forming in the next few cycles.
• Is your kombucha mother sitting on the surface of the kombucha as it brews, and is it getting thicker? If it is, then there's a good chance that the new mushroom is forming right on the top of the old one, with the two mushrooms indistinguishable from one another.
• Avoid antibacterial soap, because SCOBYs contain bacteria. Use distilled white vinegar to clean your kombucha equipment and brewing vessel instead.
• Don't add SCOBYs to hot or warm tea, because hot temperatures can kill your SCOBY. You want to add SCOBYs to tea that is room temperature.
• Avoid any foreign additions to your kombucha (such as herbs, spices, certain types of tea, etc.) unless you know that they are safe. Add flavors and foreign additions during the secondary fermentation (the bottling process), or experiment with foreign additions with your extra kombucha mushrooms. You also want to avoid herbal teas with too many volatile oils, which can harm the SCOBY over time. More about teas for kombucha brewing here.
• Keep your fermentation vessel in an undisturbed spot, and avoid environments where there is smoke, kitchen smoke, pollen, disturbing fumes such as from paints or solvents, etc.
• Use only plain kombucha as starter tea.
• Make sure your sweetener contains some form of sugar either in a dry/crystalline form (ex. evaporated cane juice or sucanat) or liquid form (ex. honey). Stevia and artificial sweeteners don't provide the necessary food for the yeasts.
• The ability for SCOBYs to ferment the tea and to produce new babies decreases as they age. Older SCOBYs are darker brown in color while younger SCOBYs typically have a creamy, white color.
• Are you using a stainless steel pot? When I accidentally brewed with an aluminum pot for a few weeks, I did not get any new mushrooms then.
• The SCOBY might be unhappy with the water. Water can vary widely, such as in the types of minerals present and their concentrations. SCOBYs don't like chlorine. Consider experimenting with filtered water, upgrading your water filter, and the length of boiling time.
• Sometimes the kombucha is ready to drink before a well-formed kombucha mushroom fully develops. If you are trying to grow a thick kombucha mother, read this post.

Source:
1. http://users.bestweb.net/~om/kombucha_balance/#No%20SCOBY

Q&A: What to do with extra kombucha mushrooms?

I've touched on this topic before, but thought it was a subject worth revisiting. What do you do with all of your extra kombucha mushrooms?

If you are brewing using the continuous method, extra SCOBYs may not be a concern. But if you are brewing traditionally, you may have more kombucha mothers than you know what to do with!

For starters:

• I usually have two kombucha mushrooms going per brew container, and the number of kombucha mushrooms you can have fermenting per container can vary depending on personal preference, the size of your brew, and the size and thickness of your kombucha mushrooms. You don't want the mushrooms to get too crowded, so experiment with what works according to your SCOBYs and brewing vessel.
• To keep or not to keep- I've found that the younger mushrooms (which are the lighter, more cream-colored ones that form at the surface of your brew) and the mushrooms with a more uniform thickness tend to perform better. So keep your preferred mushrooms for brewing, and for extra mushrooms that you need to find another use for, read some of my suggestions below.

Some options for extra SCOBYs:

• It's the perfect time to experiment with your extra kombucha mushrooms! Try different sweeteners, such as honey or maple syrup, or try herbal, flavored, or exotic teas. How about coffee kombucha? (Coffee kombucha links here and here).
• Give extra kombucha mothers to your friends and spread the kombucha love!
• Offer extra kombucha mushrooms to others through Kombucha Fuel on Facebook, The Worldwide Kombucha Exchange, Etsy.com, Craigslist, or Freecycle mailing lists
• Store extra mushrooms in the fridge in a "kombucha hotel" for backups or to distribute later.
• Ever tried eating a SCOBY?
  -Eating a kombucha mushroom by itself is not something I would probably do again. However, you may try cutting it up and sprinkling it on your food, or use it as a garnish. Alternatively, my friend suggests blending up kombucha mushrooms into smoothies.
• Feeding SCOBYs to dogs and pets is common
• Happy Herbalist lists many creative ideas and recipes for what to do with extra mushrooms, including making "drum heads and leather craft[s]!"
• Compost extra kombucha mushrooms

What do you do with your extra kombucha mothers?

Factors Affecting Your Brew

photo source: http://www.happyherbalist.com/timeandtemp.aspx

I just love this chart from Happy Herbalist, which shows how various elements in kombucha tea are affected with time. As fermentation time increases,

• The acidity of kombucha tea increases
• The pH, sugar content, and alcohol content of kt decrease

With more fermentation time, the yeasts will have more time to convert the sugars → alcohol + CO2 (a waste product that is released into the air), decreasing the sugar content.
Meanwhile, the bacteria will have more time to convert the alcohols → beneficial acids, increasing the acidity, and lowering the pH and alcohol content of the kombucha.
Furthermore, the warmer the environment, the faster the kombucha will brew- which is something to keep in mind in the colder, winter months and the hotter, summer days. Finally, another factor that speeds up the fermentation process is adding more starter tea when brewing.