Equipment 101: Brewhouse Part II

Let's finish up on the brewhouse.  In my earlier post I went over some of the basics of a brewhouse but didn't quite cover everything. In a two vessel system, the boil kettle usually doubles as the whirlpool but as a brewery expands capacity, the whirlpool is moved to a separate vessel allowing the boil kettle to start filling with the next batch of wort from the mash tun, or to begin cleaning.  The purpose of the whirlpool is to collect trub/hop particles into the middle of the boil kettle which then allows the kettle to be drained from a side port thus keeping proteins and hop matter out of the fermenter.  After the boil is complete, the whirlpool begins.  The wort is recirculated through a pump and back into the kettle via a tangential inlet in the wall of the kettle.  This creates a whirlpool effect and, due to pressure gradients on the wall and bottom of the kettle, particles collect in the center, away from the outlet port.  It works incredibly well and is quite simple to do.  Here's a little bonus tip: you can use the whirlpool to recirculate the wort while waiting for the kettle to heat up.  This maximizes the temperature differential between the molecules in the wort and the steam jackets on the sides and bottom of the kettle.  The greater the temperature differential, the faster the rate of heat exchange, meaning the wort will reach boiling much faster.  We tried this at Metropolitan Brewing and it reduced the time to boil by 20 minutes per batch for their 15 bbl kettle and it saves energy too.

False Bottom from Hell

One thing I forgot to mention in my earlier post on the brewhouse was something to consider regarding the mash/lauter tun (MLT).  The false bottom of the MLT is a perforated stainless steel plate or plates and its purpose is to hold up the grist and allow water to pass through during lautering (before and after there is no longer enough water to float the grain bed).  Most MLT false bottom plates are made of V-wire, which is simply a type of stainless wire that is welded together to create a type of mesh with slotted openings.  The problem with V-wire is that it can warp over time which can create lautering issues as gaps open around the edges and seams of the plates, especially in removable false bottoms.  Now this is apparently not a huge issue since most MLT's in craft brewing use V-wire, but it can be.  The preferred type of false bottom is milled stainless steel.  Milled plates won't warp but they are more expensive to manufacture.  Just something to keep in mind.  You'll also want the false bottom plates in your MLT to be removable for easier cleaning if possible.  Metropolitan Brewing's MLT does not have a removable false bottom and it's a little more laborious to clean.  It's not the end of the world, just yet another thing to keep in mind.

One more thing I'll cover is pumps.  When you buy a brewhouse, the manufacturer will include centrifugal pumps, usually one for vorlaufing/transferring from the MLT to the kettle, and one for whirlpooling and transferring from the kettle to a fermentation tank.  One thing I learned during my internship at Metro is to be wary of Chinese pumps.  Their quality is iffy and at least with the ones Metro have, which were included with their brew house, the manufacturer charges an exorbitant amount of money for replacement seals despite the fact that they're made in China.  Seals go out on pumps on a regular basis and they need to be replaced, which is easy to do.  Metro has since replaced one of the Chinese pumps with a Thomsen pump, made in Wisconsin, and the replacement seals can be easily purchased via McMaster-Carr (we'll talk about these guys at length later) for a fraction of the price of the Chinese ones.  Thomsen pumps are a regular in the craft beer industry and rest assured they will find a welcoming home at Panic Alarmist Brewing.

So that wraps up brew houses for now.  There's no way I've covered everything but this is a pretty good overview.  As I learn more I will share the knowledge.