I once asked Mike, “Why is Dylan foaming at the mouth?” Mike said, “Jake, that’s beer foam...I think.”
Dylan pictured far left then Mike, Jake, Chris. And yes, we were drinking when this photo was taken.
Foam. I mean, FOAM! Its like beer's name badge. It tells you that you're in for a treat- or at least it should. The foam that is on top of your beer which is in your glass which you are about to drink whilst reading this is a by-product of good brewing, good ingredients, and a well washed glass. Go ahead. Give yourself a hand. Thats some fine washing you did. Hopefully the other two are in tow as well.
Foam is a latticework of beer stuff that traps the inherent Co2 coming out of solution. The ability of that 'beer stuff' to maintain that lattice integrity is all chemistry and physics- mostly the types of chemistry and physics that doesn't call polypeptides, amino acids, minimal surfaces, tessellations, van der Waals Forces, gravitation, and osmotic pressures 'beer stuff'. But the gist of it is, foam is actually very complicated and not to be triffled with nor taken for granted. I mean who wants to drink a beer that is undergoing a destabilization of its van der Walls Forces? Not Me Man!
So, we do a few things to try and make sure that our beer is foam-worthy. For starters we try to make sure that our wort is as clean as possible before going into the fermenters. Once the wort is happy in there we keep a close eye on fermentation and bung the fermenter shut to trap as much natural Co2 as we can (we're getting better at this). Natural Co2 has a very fine bubble size and gives the beer the best possible texture and creates a very stable foam. We also force carbonate our beer to the exact level we want under a closed environment as slowly as we can. Carbing Low and slow promotes the same bubble size and keeps the surface of the beer in-tank calm.
Disturbing the beer less helps keep the gas in solution and once again, keeps the surface of the beer happy which in turn keeps all those positive foam dealios active and strong.
Sometimes the very ingredients you use before all of this occurs can cause you a brewery sized headache. For instance, lets say you use adjuncts- lets just say anything other than barley, wheat, or hops. Many adjuncts simply have enough lipids (fatty boom balatties) to do in beer foam before it ever gets started. Fats, oils, detergent residue, dirty glasses, all of these will kill foam. Also, beer that has a small hop charge or beer that is minimally carbonated will not usually support as large of a head than ones that contain more hops or Co2. (hops are sticky! Co2 makes foam!- duh)
So the next time you are at your favorite pub check out your beer's foam. As you drink, check out the lacing- how it sticks to the glass as you drink (thats one clean glass!) and think back to your lunch break when you read this shoddy information and thought to yourself, 'Man, I should've gone to YouTube".
Dylan Mosley is the Civil Life’s Brewer. He is also responsible for changing out the pirate flag every 8 months. His annual compensation package here is directly related to the amount of time his beard is a minimum of two inches long.