How much pressure can a flip top take?

Question

I'm making mead, 3 lbs honey topped up to 1 gallon with champagne yeast. My final gravity is ~1.044. Still lots of sugar in there, but fermentation had all but stopped. I put it all into 1 Liter flip top bottles. Here's the question: have I just made bombs? How much pressure can fermentation-grade flip top bottles take?

I know 1.044 is still kinda high; I don't need a lecture. I don't think that fermentation will start again, but if it does and this stuff pushes itself dry, how much pressure will that make, and can the bottles handle it?

Answer 1

The short answer is - "It depends, probably not".

Bottles are usually rated for Volumes of CO2.

Champagne bottles are typically rated for 7 volumes. Wheat beer bottles should take around 5 volumes. Ales/Lager beers are normally carbonated at 2-3 volumes.

However, flip-top bottles (I assume you mean the ones with the rubber seal) are produced in both CO2-rated and cheap un-rated beverage bottles - found in supermarkets.

As you say 1.044 is quite high - plenty of beers start around that point. This could generate a lot of CO2 (> 15 volumes) if it fermented out.

The actual CO2 volume calculations are discussed in another answer.

It might be better to transfer the mead to PET(plastic) bottles, and store them in a safe location.