February 13, 2013

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Today I got to do some things that I had already done as well as some new things.  I got a chance to do the counting of yeast cells on my own which was really cool.  It's actually not a complicated procedure.  It seems like it should be, but it's really pretty simple.  I did the count and we had really good viable yeast.

I also got a chance to observe how we prep a tank for the next batch of beer.  Tanks are interesting equipment that must be dealt with rather delicately.  While it is true that they are super strong, they are vulnerable because they are pressurized.  It is possible to over-pressurize the tank, and the emergency release valve isn't working you could cause a tank to explode.  On the flip side, if you pull too much pressure out of a tank too quickly, you could cause a tank to implode on itself.  Some thing to consider when dealing with a tank.

These are the type of tanks we were cleaning.  They hold 15 barrels of beer.

In order to clean a tank, the first thing that must be done is to drain off whatever beer or trub or yeast is left in the tank.  Once that is drained, we slowly released the pressure of the tank.  Once the pressure has been released, the first thing to do is to run some water through it to clean off the sides and top.  After just a simple rinse, we then use a caustic blend of chemicals that will pretty much burn off whatever stuff won't come off with water.  We then rinse the caustic out of the tank, and finish the cleaning process with Perasan, which is a chemical that sanitizes on contact.  We use it for sanitizing clamps and gaskets, and lots of things.  It's a very useful chemical.

The inside of a tank.  You can see the spray ball which allows us to spray water or chemicals in order to clean the sides and top of the tank

After the chemical cleaning process, the tank needs to be purged of all oxygen.  In order to do this we fill the tank with CO₂ three times and then bleed it out.  Each time what this does, because CO₂ is heavier than oxygen, is it pushes the oxygen out while the CO₂ settles to the bottom of the tank.  After the third bleed, the tank is filled with CO₂ and the cleaning is complete.  Overall the process takes about an hour or so.

In between cleaning tanks, I helped fill kegs.  It's a constant task in the brewery.