Just a quick post to record how things are going at the brewery. It has not been without a few teething problems, but we’re starting to get a good smooth flow to our processes now. Here is a picture of our leaky filter. We brew two beers and one of them filters nicely and the other one likes to leak out of the filter press. I’m not sure why. It could be that length of time the beer has conditioned before we filter it. It could be the type of yeast we use. It could be another aspect of the recipes. We do something called double filtering, which involves passing the beer through two sets of filters(coarse and fine) in the same filter press. It was leaking on the coarse side of the press, so we’ve added more filters to that side to spread the filtering duty over a wider total surface area in case that helps.
Here’s a picture of the apparatus of filling a keg of beer. We mostly use 30 litre kegs. The keg sits on a scales so we can accurately judge how much we’re putting in and how fast we’re filling it. This relies on the wonderous properties of the metric system that one litre of water weighs exactly one kilo. Beer is ever so slightly heavier than water, but we can still calculate precisely how heavy 30 litres will be. We can tell how fast we’re filling the keg from how quickly the weight is climbing. If you fill a keg too quickly, you get a lot of foam breaking out. This means that if we simply relied on foam coming out the tapping head to indicate whether the keg was full, we might underfill kegs (since a keg full of foam in the brewery would translate into a mostly empty keg in the pub when the foam had died back down). The tapping head is connected both to our carbonator and a separate supply of gas. The carbonator supplies the beer with a desired level of CO2 gas in it, and we use the separate gas supply to purge all the air out of the empty keg before filling (to avoid staling oxidation reactions), and to provide a small countervailing pressure in the keg to make sure that the gas dissolved in the beer doesn’t break out of solution when it is put in the keg. We’re aiming for what we call a black fill, where the beer is put in the container without any foam breaking out.