By: Brew Your Bucha Posted: September 20, 2017 in Kombucha

A Symbiotic Colony of Bacteria and Yeast (SCOBY or culture) is one of the key components to producing kombucha.  A healthy and happy SCOBY will not only provide you with many brews of kombucha, but also give you a supply of baby SCOBY.  Novice and veteran kombucha brewers alike have questions about whether their culture is healthy; here are some tips to check whether it is healthy or not:

Common Variations of SCOBY

Each batch of kombucha will be unique as a result of factors, such as temperature, type of tea and/or sugar, duration of fermentation, size of SCOBY, size of jar, etc.  Your SCOBY may react differently to each of these components which could impact its health.  It is common that your SCOBY will have one or more of the following variations:

  • Growth - if you continue to use the same SCOBY to brew, it will grow to the same diameter of the brew jar.  However, it may not grow uniformly and some sides may grow thicker than others.
  • Babies - your original culture may be "fertile" and reproduce to form a baby.  Baby SCOBY tend to appear as a film on the surface of your brew and thicken over time. It may fuse to your original SCOBY; however, if your brew jar is disturbed it may separate which does not impact your brew.  If you allow your baby to grow, you can separate it from the original SCOBY and use this in a separate brew jar to increase your brewing capacity.
  • 'Floaters' - brown/dark yellow strands may form and attach to the SCOBY, which is completely normal.  If these strands break off from the SCOBY and become sediment at the bottom of the brew jar, you can strain them out before your second ferment.  These are byproducts of the yeast culturing the sweet tea.
  • Position - your SCOBY may float, hover in the middle of the brew jar, or sink to the bottom.  It may also stay verticle or lay horizontally; however, these don't indicate whether your SCOBY is healthy or not.  Your SCOBY may be reacting to the conditions of your brew including the humidity level of the area in which it resides.

Indications of Potential Concern

Primary health concerns for your culture can include mold, inactivity, and contamination from bugs/pests.  These concerns are uncommon if you follow the instructions in our Learn to Brew page; however, if they do occur, here are the signs:

  • Mold - typically, mold develops if the culture is exposed to contaminates and/or is not cultured at the appropriate pH levels (between 2.5 and 4.0).  If you use the appropriate types of water, tea, and sugar, the starter fluid typically is acidic enough to prevent the development of mold.  Indications of mold will be a formation of black, white, green, and/or red spots on your SCOBY or on the inside of the brew jar.  In many circumstances, the mold will also look fuzzy, similar to what you would see on moldy cheese.  If mold develops, the most common cause is forgetting to use the correct amount of ingredients or forgetting one altogether.  Some other potential causes of mold developing are:
    • mold spores already in tea used for kombucha brewing
    • improperly sanitized equipment and utensils while brewing
    • handling the SCOBY with contaminated utensils or unsanitized hands
    • mold spores in the air around the brew jar
    • brewing your kombucha too close to other fermented foods

If you see mold developing, dispose of the entire brew (including the culture) and restart your brew with a new SCOBY & sanitized utensils and jar.

  • Inactivity - During the brew process, your sweet tea will begin to smell like vinegar; this is the result of the culture converting your brew into kombucha.  After a few days, you can smell or taste your brew to determine if your SCOBY is making your kombucha; if not, then you will need to assess whether the location of your brew is too cool.  If you move your brew to a warmer location or wrapping it in a towel, this may help your SCOBY stay active.
  • Bugs/Pests - Ants, fruit flies, and other insects are attracted to your sweet tea and kombucha; therefore, it is very important to properly secure a cloth cover or cheese cloth to the mouth of your brew jar.  This will help prevent them from coming into contact with your brew.  If fruit flies or house flies come in contact with your brew, they may infest your SCOBY with maggots.  Discard your entire brew if there is any indication of contamination.  Restart your brew with a new healthy culture and thoroughly sanitized utensils and jar.

pH Level 

If you are a novice to kombucha brewing or if you are trying different variations of ingredients, it is recommended to test the pH level of your brew.  Your kombucha should fall in the pH range of 2.5 and 4.0 prior to consumption; this will provide you with some comfort in knowing your brew is at the appropriate acidity to taste.  If it falls outside of the range, you can wait a little longer and retest.  Although it is uncommon for a batch to fail, you may want to consider disposing of the batch and restarting.

If you have any questions about your SCOBY, you can visit our FAQ page or connect with us directly through our Contact Us page.

Brew On!

Chris & Derek