By Colin Preston
Reutilizing used tanks can be of great time and cost savings when setting up or adding on to a brewery or winery. Good used tanks don’t always come cheap. It is important to know what to look for in order to make a wise investment as quickly as possible. Often a used tank will sell within a week of being posted. This article highlights a few key points that will help you know what to look for before investing on a used tank.
Tank capacity can be somewhat confusing. Most beer tank volume is expressed as “working” volume instead of gross volume. To make things more confusing, each different kind of tank has a different ratio of working capacity vs gross capacity. A simple generalization of these ratios are as follows: a fermenters gross volume is generally 120-133% of its working volume; a brite: 115%. Brewhouse tanks (kettle, mash/lauter tun, hot liquor tank): 150%. So a 7bbl ”working capacity” fermenter would have a gross capacity of 8.5bbl-9.25bbl. If you’ve ever filled a 5gallon carboy to the brim before pitching yeast, you know why this extra “headspace” is important! Keep these ratios in mind to ensure that you get the right sized tanks for your operation.
Shell smoothness is a very important part of tank sanitation. It is possible for a blemish on the inside of the fermenter to hold some minute microorganisms, which can infect the next batch. Keep an eye out for rough spots, pin-holes and cracks in welds, deep scratches, pits, and CIP shadows. These blemishes might be sanitized by washing or CIP, but perhaps, one time, regular cleaning does not get them 100%, and you lose that next batch. Interior welds don’t necessarily need to be blended completely smooth, but they should be free of defects (no cavities, craters, pits, etc), smooth to the touch, and easy to clean.
Threaded fittings are another noteworthy source of infection. This is a more critical point for beer production than wine production. If there are threaded fittings on the shell which are allowed to come into contact with product, their removal and replacement is strongly advised. It is nearly impossible to ensure that the grooves inside of these fittings get thoroughly sanitized between batches. The most common accessories which utilize threaded fittings are sample valves and temperature probes. These accessories should be removed and boiled between batches to ensure good sanitation.
Does the tank that you’re looking at come with accessories? Clamps, gaskets, valves, accessories… the cost of these items adds up fast! It is also a good idea to have extra tank-specific gaskets on hand. Find and keep a spare manway gasket on hand.
As with any major investment, a third party consultation is always advisable. The excitement about a new purchase can cloud judgment. It is always helpful to have a non-partisan set of eyes give you a second opinion, be it a fellow brewer, or a professional tank builder.
Colin Preston is the founder and Chief Everything Officer of Practical Fusion, a stainless steel tank manufacturing company, which began in his Oregon City garage in 2009. You can check them out on Facebook, or at www.practicalfusion.com