How does bottling in a half bottle effect taste

Question

I just finished my first batch, a Brooklyn Brew 1gal kit, and was unable to split the batch evenly over 8 bottles so I ended up with 7.5. When I went to taste the beers after two weeks in the bottles I received 2 very different flavors between a full bottle and the half bottle. What is the cause? and how can I prevent this issue in the future?

Additional information: I was using 22oz Grolsch bottles and was able to put in about 12oz into that bottle. Since I didn't have a capper I stayed in the same bottle. I did not individually sugar the bottles but placed the maple syrup(in lieu of sugar) directly into my pot. The flavor was more tart and flat compared to the others.

Answer 1

A few possible reasons come to mind:

1. If you have added the same amount of sugar to each bottle (as opposed to adding directly to your bucket) then you have different "gravities" and depending on how much it's fermented, different flavour profiles.

2. If you have left a large headspace in the bottle during the carbonation phase, you might find that the carbonation has not absorbed into the beer itself, rather into the headspace. CO2 has it's own flavour but carbonation affects mouthfeel and flavour too.

3. When bottling that last beer, if you weren't able to get a full bottle's worth of beer, you likely got a fair bit of yeast and/or trub along with the beer. This will significantly affect flavour.

If you provide some detail on the different flavours (e.g. bready, bitter, tart, fuller) we could help figure out which is most likely. My money is on #3 though.

Answer 2

The problem:

• As C4H5As said, the half-full bottle may have been under-carbonated due to having so much headspace.
• You also may have had more oxidation due having so much more air in the bottle initially. John Palmer has a list of Common Off-Flabors and says that oxidation causes "wet cardboard or sherry-like flavors".

The solution:

• When I'm bottling, I try to avoid this problem by using a mix of 12oz and 22oz bottles. If you're using 12oz bottles and get to the end and realize you only have half a bottle left, carefully pour it into a 22oz bottle with one of your full 12oz bottles. Or if you're bottling in 22oz bottles, pour the half-empty last one into a 12oz bottle.

• These problems can also both be avoided by force-carbonating in a keg and then flushing the bottles with CO2 before filling, but I assume that's way beyond you at this point.

(I prefer to use 22oz bottles in general, since they're more fun to share and require less work to clean and bottle. But they're harder to obtain.)