CAPPING & SECONDARY FERMENTATION
Welcome to capping and secondary fermentation. As you filled each bottle you will have left a 1 or 2 centimetre gap at the top of the bottle. We don’t fill our stubs all the way to the top because the yeast activity in the bottle fermentation stage creates CO2, or bubbles, in the beer which will cause the bottle to release its cap in a most violent and inconvenient way when you least expect it. By leaving a gap, the CO2 can form and then become dissolved into the beer, thus creating the miracle of carbonation. This is also why an accurately pre-measured dose of sugar is beneficial.
At this point many homebrewers simply cap the bottles using a contraption known, conveniently, as a ‘capper’ and move on to the storage stage. My research has uncovered a beer theory, or beerthory, which may or may not have some merit. Some homies suggest that by capping immediately you can trap oxygen in the top of the bottle neck and oxygen is a sworn enemy of beer. It creates ‘oxygenation’ which can affect the taste of the finished beer. Of course, oxygen itself is not a bad thing for beer altogether. The ‘O’ in CO2 is, after all, oxygen and pouring a nice beer into a glass allows oxygen to release the full range of flavours which would otherwise be wasted on you and then, if you yourself didn’t have oxygen, well, you’d be dead and then the whole beer thing would really be wasted on you, wouldn’t it?
The suggestion is that, by sitting the caps onto the bottle and resting before capping, the CO2 activity will push the oxygen from the space in the neck of the bottle and replace it with CO2 only, thus preventing oxygenation. I might give this a go out of interest alone and let you know if I can detect any difference at all. My thoughts are that the amount of CO2, or oxygen for that matter, is pretty minimal in the overall scheme of things and CO2 contains oxygen anyway so I don’t imagine that even Beery McBeer-Beer* the famous beer taster would be able to detect any difference in the final tasting. Just move on to capping.
There are a few ways of securing the cap onto the bottle, most of which would be right at home in a museum for instruments of torture or stupidity when compared with the options available. Mallets and cap holders of all shapes and sizes are illustrated in homebrew books and catalogs but they are quite simply prehistoric when compared to a bench capper. A bench capper is also a lot safer on the bottles and on the user. Why would you want to hit your beer with a hammer when you can just pull on a handle?
The final step is to tilt and turn your bottle a few times to properly mix the sugar or kick start the carbonation drop and then set your stock aside at room temperature for at least two weeks. I like to give mine at least four and I prefer six weeks. Many swear by two months. As long as the beer has time to carbonate. Check by drinking at two week intervals.
This is a longish piece by Beer Bloke standards but I think if it helps someone to make more and better beer then it’s OK. Over 17 batches I have tried to streamline the process by trying different techniques and as long as you don’t sacrifice sanitation and cleanliness for speed then anything that encourages more people to brew can only lead to a better society for everyone.
Cheers,
Prof. Pilsner
*There is not really any real person called Beery Mc Beer-Beer. I just made him up for effect. I based him on Homer Simpson’s ‘Hootie Mc Boobs’.
