I have been thinking of buying a plate chiller for the last year for a few reasons: 1) it takes less time to chill the wort than my current copper wort chiller, and 2) it uses less water. So I believe there are two main options when buying one; either a closed plate chiller which cannot be taken apart or a design that can.  What are the ups and downs of the two and how do you go about cleaning them to ensure the precious wort is bug free?
Rossa O’Neil
Dublin, Ireland

This is a good question in that there is not a single answer. The company that puts bread on my table manufactures plate heat exchangers, among many other things stainless, and we also use brazed plate heat exchangers for certain purposes in some of the processing systems we manufacture. In heat exchanger lingo a plate heat exchanger, often referred to simply as a PHE, is made of plates where the cooling or heating medium is on one side of the plate and the product is on the opposite. In many applications it is desirable to be able to dissemble the PHE for maintenance, inspection and/or cleaning. When this functionality is required the units are bolted together and the plates separated by gaskets.
   
Another type of PHE is the brazed plate heat exchanger. These are typically used where disassembly is not required or the added cost required to make the unit serviceable is not worth the money. Brazed PHEs are normally used for simple utility duties where there is not “clean” product involved. For example, if you want to heat water with steam and use the hot water in a secondary heating application the brazed PHE is a decent choice.
   
When our customers are heating or cooling a food product, a PHE designed to be disassembled is the go-to heat exchanger. Typical examples include wort cooling, beer cooling, wine attemperation, hot water production using steam, solution heating in CIP (clean-in-place) systems and flash pasteurization units.
   
Brazed plate heat exchangers are cheaper, however, the problem with the brazed PHE is that you cannot disassemble the unit and this makes some people uncomfortable. On the other hand, the brazed PHE has become quite popular for homebrewers because they are available in small sizes and they are priced to fit the homebrewing budget. While I would never sell one of these units to a commercial brewer for wort cooling, I would recommend them, with caution, to a homebrewer.
   
The biggest problem with PHEs in general is that solids can become trapped within the plate pack. When wort coolers collect solids things can be a problem because, as you state, microorganisms can (and do) grow. When this occurs the wort cooler becomes a wort contaminator.
   
So what is a homebrewer to do? If you have the funds and really don’t mind spending the extra money, a small PHE designed to be taken apart is my first recommendation.
   
If you choose to purchase a brazed PHE I strongly advise putting some sort of coarse filter in front of the unit to trap bits of hops and trub. This can be something as simple as a section of stainless steel scrubby pad on the inlet of your wort siphon or on the outlet of your kettle if you have a valve.
   
After use I would clean the unit by thoroughly rinsing it with water and then I would “pack” the unit with a 2–3% solution of sodium hydroxide (commonly known as lye or caustic) or a less alkaline cleaner, such as Powdered Brewery Wash (PBW). Allow the cleaner to sit in the PHE for at least an hour before rinsing. This will help to remove protein soils that form films on stainless steel surfaces. As with all cleaners it is important to exercise caution at home.

I am making a classic style Pilsner and was wondering how long I can lager the beer in the secondary fermenter and in the bottles?  Is two months in the secondary too long?  Should I condition it longer in the secondary or in the bottles?
Dave Wood
via email

I think this question probably will generate two very different answers depending upon who you ask. In this case you asked me and will get my take on it.  Let’s back up . . . why lager beer at all?  The most common reasons cited for lagering, or aging before serving, are diacetyl reduction, acetaldehyde reduction, clarification
and carbonation.
   
Some folks talk about flavor maturation, flavor mellowing and beer stabilization when they talk about lagering, but these are all different terms for the four objectives I cited. The only thing that should be performed before bottling is clarification, and this only needs to be done partially since yeast is needed for bottle conditioning and the bottle bottom serves reasonably well to keep yeast sediment out of the beer, provided that some care is exercised when moving bottles around and when the beer is poured.
   
I suggest fermenting your lager until the final gravity is stabilized and then allowing it to sit at the fermentation temperature for a few days to give the diacetyl and acetaldehyde reduction steps a solid head start, if not more than enough time to be complete. Move the beer to a cold place, such as a refrigerator or snow bank for about a week.  The cold temperature will knock a lot of the yeast out of solution and make racking easier prior to bottling. I then would rack, prime and bottle.
   
If you want to hold your Pilsner for a couple of months prior to drinking I would suggest the hold step after bottling because the bottle has everything you need for lagering; yeast, beer, fermentable sugars and a mechanism to hold the carbon dioxide in the container (the bottle cap). This is of course not traditional for lagers. Most lagers brewed in the old days, which is what brewers often reference when discussing “traditional” methods, were aged in large tanks or barrels and then moved into smaller barrels where they would be transported to the tavern for serving.