Brewing ginger beer and over carbonation

Question

I've been trying to make ginger beer and the first attempt bombed, for some reason. I'm not clear if it's because of residual bleach, or tap water at the wrong point, or what. I was about to give up and toss the ginger bug out when I saw it was relentlessly fizzing so I gave it another shot.

I bottled the 4L of mixture (with 200ml of Ginger Bug) into flip-top bottles. Twenty four hours later I wanted to check the carbonation, so I opened the first bottle. It blew the cap right off and dumped about half the bottle's contents on the floor. The other three bottles were pretty much the same, although I managed to open them more carefully.

My question is - what can I do to avoid this in the future? This is the first thing I've "brewed" - is there some equipment specifically to address this problem? Some jug with a pressure valve?

Does releasing the built up pressure in a bottle harm the carbonation of the beer? I know opening a bottle of coke will make it go flat, eventually. How is it different for ginger beer?

Answer 1

I like my ginger beer somewhat sweet and carbonated. This means that, at some point after bottling, the fermentation/carbonation process must be stopped. To determine this point, I bottle as normal (in glass bottles), but I also bottle one 500ml plastic soda bottle (an empty PET bottle, like coke, mineral water, etc.).

I test this bottle daily to check the pressure simply by squeezing it. When it feels the same as an unopened soda bottle, it is time to stop the carbonation. This is done by pasteurising the glass bottles (to kill the yeast and stop the process).

To pasteurise:
1. Heat water in a large pot to a temperature of about 85C (185F).
2. Very important: Remove the pot from the heat source. If you don't the next step will very probably cause the bottles to explode.
3. Carefully place up to about 8 bottles in the pot of heated water.
4. Make sure that the water level is above the level of the ginger beer in the bottles.
5. Leave it standing for at least 10 minutes.
6. Remove and place it somewhere where it can cool down naturally.
7. Refrigerate.
8. Enjoy!

If you're bottling in PET bottles, the easiest way is to cold crash. Place the bottles in a refrigerator. The low temperature will make the yeast go dormant or, at least, slow the process down significantly.

Answer 2

It sounds to me your ginger beer is still fermenting inside the bottle. When this happens, it creates more co2 and creates more pressure inside your bottle.

Perhaps when you add your ginger bug into the bottle, yeast is activated and starts/continue to carbonate more, hence the pressure build up.

Does releasing the built up pressure in a bottle harm the carbonation of the beer?

If your beer is still fermenting, then no. Once you release the carbonation pressure, and close the lid back, your beer will continue to ferment and carbonate and pressure will build up again. If it continue to ferment too short, then you'll get less carbonation.

If your beer has finished carbonating, and you open the lid, then when you close it, you'll have all the carbonation gone. There should still be carbonation in your beer, so test it if it's enough for you.

Or maybe open the lid after 12 hrs, and test for carbonation when you're ready to drink. If carbonation is good, keep it, if it's too much, then open after 16 hrs etc. If carbonation is too less, then open lid after 6 hrs, and keep decreasing it until you find the right amount.

This is the first thing I've "brewed" - is there some equipment specifically to address this problem?

Have you tried putting your ginger bug inside your keg and let it ferment a bit there? Then bottle it as normal.

Or put less ginger bug in? Test with half, and see if it fixes your problem. Test if the flavour is enough for you though.

I know opening a bottle of coke will make it go flat, eventually. How is it different for ginger beer?

Opening a bottle of coke, makes it go flat because your cap is not air tight. If it was air tight, it will hold the carbonation. There's no difference to ginger beer, all is the same, and has to do with fermentation and carbonation.