Tuesday, May 31, 2016

What goes up...

I've been doing some more brewing lately; it's in readiness for a party coming up in June to celebrate my Sister's 50th birthday. I thought I'd knock up some brews for the boys (and beer loving girls) in the family (and extended family) and as there's going to be quite a few people there I'm aiming to have quantity, quality and range covered so that people can find something they enjoy and have enough to keep them going throughout the day. 

As I've been doing a few batches I thought I'd record the life-cycle of a typical brew as a series of three photo's taken at zero hours, 6 hours and 7 days (when the main changes occur) In this first snap we see the fermenter full of fresh (un-fermented beer) at this point all the crud (proteins and fatty acids) are starting to settle out, you can see them as a cloudy haze of particles gradually sinking to the bottom of the container and separating from the sweet wort which is the beer coloured liquid at the top. At this point the yeast is mixed up with this mush and takes a few hours to really get into its stride.

This picture was taken after 6 hours, something rather odd has happened, all that fluffy crud has suddenly risen to the top of the vessel. The cause of this is that the yeast has now started working and is munching its way through the sugars in the wort. As it does this carbon dioxide gas is produced and the tiny little bubbles rise through the liquid and cause the whole lot to clump at the top, sometimes this is so violent that stuff starts leaking out, hence the tube you can see which directs the overflow into a suitable container should that happen. The beer stays like this for about 3 days as it passes through its most active fermentation phase.

Now we see the beer 7 days into the process, as you can see the fluffy crud that was being held up by carbon dioxide bubbles is now no more. The yeast has polished off most of the sugars in the wort (converting them to alcohol) and the whole thing is now properly beer! The remaining clumpy bits have sunk to the bottom again where they will gradually compress down. The beer is drinkable at this stage but isn't fizzy, to get a fizz into it you need to put it in some bottles with an air-tight cap along with a little extra sugar to get the remaining yeast to generate some more carbon dioxide to carbonate it. Sometimes to get the beer really clear I put the whole thing in the fridge for a couple of days at 3 degrees centigrade, this causes most things to come out of suspension and makes the final product crystal clear.

The batches I make are small, only a gallon at a time (8 pints) so I'll be doing half a dozen or so in enough time to allow them to condition properly in bottles before unleashing them on an unsuspecting public, let's hope they come out OK!


Chairman Bill said...

Looks suspiciously like bomb making equipment to me!

Steve Borthwick said...

CB, at 8.5% my "Imperial IPA" might just blow your head off ... :)