A friend of mine used plastic bottles with plastic caps (like coke bottles) for bottling. He used sugar (Granulated Sugar of Sugar Beet) for priming.

It turned out those plastic bottles have problems with caps and the bottles lost too much CO2. The bottles have very liitle to no carbonation right now. He wants to recover those bottles somehow.

He does not have any equipment for CO2 flasks or tanks, so he will use sugar or malt for this purpose

A few questions over this issue:

  1. Is it safe to transfer plastic bottles to bucket and refill glass bottles (which are suitable for standard single-use caps) or changing the container is not safe?
  2. Can he re-add priming sugar (the same granulated suger or dextrose or malt extract) to bottles? Will currently existing yeast within beer be enough for this or will he need to add more yeast prior to adding priming sugar?
  3. Any other steps while doing above?

1 Answer 1


There should not be a problem using PET bottles for holding gas pressure. These are commonly used for other carbonated beverages. My local store sells new PET bottles for the express purpose of brewing.

Decanting the bottles back into a bucket (or suchlike) should be fine. Just ensure sanitary conditions - of both the vessel being filled, and the new bottles. You also want to minimise oxygen pickup - not sure this will be possible.

IF the previous priming sugar was consumed, it should be OK to re-prime. There is likely enough yeast already (unless you removed it somehow), there will be extra yeast sediment later. Please be careful that the previous priming sugar was used-up - otherwise you could be double-priming the bottles, potentially leading to a dangerous over-carbonation of the glass bottle.

So, we come to a question: Are you sure it was the bottles?

Without knowledge of the full details ... I would not re-prime the bottles. The bottles could have little to no carbonation due to:

  • Yeast simply has not had enough time to work
  • The ambient temperature was too cold, and the yeast slowed right down
  • The beverage in question has a high (> 7%) alcohol content that is slowing/stalling priming

The first 2 points are the likely culprits.

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