Kombucha Brewing Containers **
Must be
- Visibly clean and reasonably well-sanitized (but definitely NOT sterilized!)
- As free as possible from chlorine and other chemicals that can leach into or out of the container material
- Sturdy enough to withstand the fairly acidic brewing conditions that may further cause chemicals to leach out from the container material, e.g., at pH's below 3.0
Possible Brewing Container Materials
A. Glass
B. PolyEthylene Terephthalate, #1 PETE, PET
C. High Density PolyEthylene, #2 HDPE
D. PolyCarbonate, #7 PC, "lexan"/"nalgene"
E. Stainless Steel Metal, SSM
A list of references concerning plastic brewing-container materials B thru D is at my blogpage Various Plastics-related SitesA. Glass.
1. Wash with warm soapy tapwater, rinse.
2. Sanitize using 1-2 tbsp household bleach and cold water, leave in shade or low-light at least 6hrs.
3. Re-wash with warm soapy tapwater, rinse well with warm
non-soapy tapwater.
4. Rolling-boil 2-4 quarts of tapwater containing 1-2 tbsp standard food-grade vinegar for ~5 minutes to reduce chloride, cool this enough for easy handling, fill the glass container with this medium-hot acidic water for ~5 minutes, and re-rinse with cool filtered water.
5. Check container for any noticeable discolorations or odors, and check for these
before adding the combination of nutrient broth and SCOBY.
B. PolyEthylene Terephthalate / #1 PETE.
1. Wash with warm soapy tapwater, rinse.
2. Sanitize using 1-2 tbsp household bleach and cold water, leave in shade or low-light at least 6hrs.
3. Check for any leaks at container seams and at container bottoms.
4. Re-wash with warm soapy tapwater, rinse well with warm
non-soapy tapwater.
5. Rolling-boil 2-4 quarts of tapwater containing 1-2 tbsp standard food-grade vinegar for ~5 minutes to reduce chloride, cool to well below 50 degrees Centigrade (that is, well below 130 degrees Fahrenheit), fill the #1 PETE container with this warm acidic water, leave in container ~5 minutes, and re-rinse with cool filtered water.
7. Check container for any noticeable discolorations or odors, and check for these
before adding the combination of nutrient-broth and SCOBY.
C. HighDensityPolyEthylene / #2 HDPE.
1. Wash with warm soapy tapwater, rinse.
2. Sanitize using 1-2 tbsp household bleach and cold water, leave in shade or low-light at least 6hrs.
3. Check for any leaks at container seams and at container bottoms.
4. Re-wash with warm soapy tapwater, rinse well with warm
non-soapy tapwater.
5. Rolling-boil 2-4 quarts of tapwater containing 1-2tbsp standard food-grade vinegar for ~5 minutes to reduce chloride, cool to well below 50 degrees Centigrade (that is, well below 130 degrees Fahrenheit), fill the #2 HDPE container with this warm acidic water, leave in container ~5 minutes, and re-rinse with cool filtered water.
7. Check container for any noticeable discolorations or odors, and check for these
before adding the combination of nutrient-broth and SCOBY.
D. PolyCarbonate / #7 PC .
1. Wash with warm soapy tapwater, rinse.
2. Sanitize using 1-2 tbsp household bleach and cold water, leave in shade or low-light at least 6hrs.
3. Re-wash with warm soapy tapwater, rinse well with warm
non-soapy tapwater.
4. Rolling-boil 2-4 quarts of tapwater containing 1-2 tbsp standard food-grade vinegar for ~5 minutes to reduce chloride, immediately fill the #7 PC container to the brim with boiling acidic water, leave the hot acidic water in the #7 PC container until cool enough to handle, then dump the acidic water, re-rinse with cool filtered water and completely dry out the container.
5. A repeat of step 4 may be called for due to the presence of BisPhenol A (BPA) and other leached chemicals remaining in the #7 PC following the bleach-sanitization of step 2 above.
6. Check container for any noticeable discolorations or odors, and check for these
before adding the combination of nutrient-broth and SCOBY.
E. StainlessSteelMetal / SSM.
1. Wash with warm soapy tapwater, rinse.
2. Sanitize using 1-2
teaspoons Iodophor and cold water, leave as is for 1-2hrs.
3. Re-wash with warm soapy tapwater, rinse well with warm
non-soapy tapwater.
4. Rolling-boil 2-4 quarts of tapwater, cool this enough for easy handling, fill the SSM container with this medium-hot water for ~5 minutes, and re-rinse with cool filtered water.
5. Check container for any noticeable discolorations (with SSM, this may be rust!) or possible odors (e.g., unrinsed iodine), and check for these
before adding the combination of nutrient-broth and SCOBY.
** Much thanks for all this wholeheartedly go out to my neighbor, the NAPCOR people (for technical advice on the use of PETE/PET plastic), and
so many very helpful people besides these!
My own kombucha-container results so far are as follows:- Narrow-mouthed jars in general are poor as primary fermenters. I found in at least one case that transferring the SCOBY out of such jars caused the SCOBY to become contaminated with visible mold -- likely contracted when I had to directly handle the SCOBY.
- Wide-mouthed glass jars work excellently as primary fermenters, but only work acceptably as secondary/carbonation-fermenters. The problem with the latter is not with sanitization; the problem appears to be with carbonation-gas escaping through the caps on top of such containers.
- Wide-mouthed #7 PC jars work excellently as primary-fermenters (IMO, very nice SCOBY "mushrooms"!) This material works just as well for secondary/carbonation-fermentation, however, it is imperative that the lids on such jars be kept as tight as possible from the start of the 2ndary fermentation all the way through final refrigeration.
- SSM containers work poorly as primary-fermenters... I'd guess that either impurities or something else in the metal reacts with the SCOBY-produced acidity to negatively affect the SCOBY's growth at a critical stage. Surprisingly, SSM jars seems to work exceedingly well for secondary/carbonation-fermentation. SSM container-sealers are clearly the most airtight of all the above materials.
- Those persons who have direct experience with this, have emphatically described to me that both Low-Density PolyEthylene (#4 LDPE) and PolyPropylene (#5 PP) work poorly as kombucha-fermenting containers. I would guess that sanitizing agents and other chemicals can most easily both absorb into and leach out of these softer plastics. Every general-purpose water bottle or Rubbermaid product I have come across over the last fifteen years or so has consisted of either #4 LDPE or #5 PP.
- #3 PolyVinyl Chloride (PVC) is considered toxic due to this plastic's release of phthalates, so this material should NEVER come into contact with kombucha.
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In retrospect partially based upon the above, much of the continuous problems I had in my ale-homebrewing back in the old Brooklyn basement apartment were caused by the following:
- Using 5Gal Poland Springwater carboys made of PolyCarbonate (PC, #7) instead of being made from glass
- Using way too much bleach left for way too long in 5Gal PC carboys, all this performed in order to attempt to thoroughly sanitize them!
- Using ineffective methods to rid each PC carboy from chloride and other NYC-water residues before brewing --- should have washed the sanitized PC carboys with warm soapy tapwater, then completely rinsed these with regular non-soapy warm tapwater, then added boiled tapwater (to leach out more chloride+residues), and then finally, rinsed these with cool distilled water (or alternatively, with filtered, chloride-reduced water!!)
- Having relatively-high ambient apartment-temperatures around my homebrew-fermenting carboys, even after the wort was sufficiently cooled!
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