Optimization of Chitosan Finings
How We Got Here:
As a professional brewer, I have had a bitch of a time fining my lagers fermented with WLP833. This was never a problem as a home brewer. I used to fine with Jell-O, and it worked fine. Jell-O has not produced the same results at my current brewery. At the old brewery, I had a centrifuge and a couple of filter options. These days, all I have to work with is fining agents, and tank time. With first generation yeast, it typically takes me 17 days in the FV (Fermentation Vessel) before the beer will pass a VDK test (vicuna diketone). It then takes another 45 days before it will drop brite in a Brite Beer Tank. (BBT, in my brewery we call it a BT.) For production reasons I would like to be able to produce tasty lager beer in 4-6 weeks of total tank time. When I have spoken to other brewers in my area who ferment with WLP833, they seem to have the same issues I have. Getting this yeast strain to react with fining agents seems to be a challenge for many brewers. My buddies that use this yeast, filter it after fining. After quite a while of beating my head against the wall, I found a thread on probrewer.com. It seems a fellow at another brewery had found a formula for getting this yeast to play nice with brewers. He used a silicic acid based fining agent called Kieselsol, in conjunction with a product called Chitosan. In 21 days he was having damn near brite beer ready to filter. In my brewery we have played with a product called Biofine clear. It is also made of silicic acid. I ran an optimization test on my beer with it, and dosed it into my beer using a re-circulation loop. My next step is to fine with Chitosan 48, hours after the Biofine. Of course, the folks who sell Chitosan recommend running an optimization test, but supply no procedure. No problem. I like to pretend I am a Scientist!
How I Came Up With The Method:
The dosing rate for Chitosan is 150mL-200mL of Chitosan, per hL of beer. Well, here on the west coast of the USA, we work in US BBLs. However, we also like to measure things in mL, in graduated cylinders. (oh, the joys of being an American brewer!) I need numbers, and dosing rates I can work with. One US BBL is 31 US gallon, or 0.85hL. This converts to 127.5mL-170mL of Chitosan, per BBL of beer. To avoid trying to measure extremely small amounts of Chitosan, we create a diluted base solution of the product. This makes it easier to work with. I decided a 1/16 dilution would give me volumes that were easy to work with. You will dose small measured amounts into a standard amount of beer. I find 250mL of beer works well in 12oz beer glasses. You will want to make sure you have enough base solution to dose all your samples.
(5) 12oz Beer glasses, or 250mL beakers.
(1) 50mL Graduated Cylinder.
(1) 2mL Pipet.
(1) Aspirator Bulb.
(1) Cup of locally sourced, fair trade, hippy-dippy coffee.
Using the pipet, measure 2.75mL of Chitosan into a 50mL graduated cylinder. Next, top it up with water to the 44mL mark. Finally, transfer this to a 50mL beaker.
Using a 500mL graduated cylinder to measure, fill (5) 12oz beer glasses with 250mL of beer each. Use blue painters tape to number the glasses 1-5.
Using a 2mL pipet, dose the glasses with 6.0, 6.5, 7.0, 7.5, and 8.0mLs of beer. Once you have dosed your glasses use your pipet to mix the thoroughly. Cover the glasses with foil, and store them refrigerated for 24 hours.
6.0mL of solution contains 0.375 mL of Chitosan.