Stainless steel is a preferred material in the brewing industry because of its durability and ease of sanitation. But before stainless steel can be sanitized, it has to be cleaned. One of the more common things to remove from the surface of stainless steel is what is known in the industry as beer stone.

Beer stone is more or less calcium oxalate. It appears as a brown or brownish-white film on the inside of your stainless steel fermenting tanks. It is not harmful in its initial stage is. However, if it is allowed to build up in excess amounts over time, it can alter the taste of a beer and make it difficult to sanitize the tank.

Unfortunately, beer stone buildup is inevitable for stainless steel brewing. That is why some commercial breweries continue to use copper tanks and kettles. There is a trade-off, though. Copper has its own concerns that breweries need to worry about. One way or the other, there is work involved.

Why Beer Stone Accumulates

The science behind beer stone accumulation is actually quite fascinating. During stainless steel brewing, wort is heated for a time. Believe it or not, the wort doesn’t actually come into direct contact with the surface of the tank. There is a thin layer of air between the two.

As the calcium oxalate separates from the liquid, it travels through that thin layer of air and bonds to the stainless steel. You could say that it almost gets baked to the surface. Every new batch of beer brewed between cleanings adds yet another thin layer.

Cedar Stone Industry out of Houston, TX says that beer stone accumulation is completely normal with stainless steel tanks. It is nothing to be alarmed about. As for cleaning kettles and tanks, the best bet is a little bit of elbow grease combined with a plastic abrasive.

Removing Beer Stone

Breweries all have their preferred methods for cleaning stainless steel tanks. Different methods are utilized depending on what is being addressed. For example, certain kinds of acids, like phosphoric and muriatic, are helpful for reducing beer stone. Nitric acid may be utilized to offset the effects of a caustic cleaner, but it can cause surface pitting.

Caustic cleaners are alkaline cleaners that commercial breweries use to remove organic debris. They can be used in a home brew setting as well, but they should be used with caution. Caustic cleaners can be harmful if direct contact is made. They also tend to increase calcium buildup if they are not neutralized by an acid or completely washed away themselves.

Assuming all one has to do is remove beer stone, some sort of plastic abrasive pad works extremely well. You wet the surface with warm water then scrub vigorously. The beer stone should come right off. However, it is important not to substitute with steel wool or a kitchen scrub pad with soap added to it. Stainless steel can introduce rust while a soapy kitchen pad can leave unwanted residue behind.

You’re Doing It Right

If you are practicing stainless steel brewing at home, expect to see beer stone build up. A regular build up is an indication you are doing something right. Every time you have to break out the plastic abrasive and elbow grease, consider it a badge of honor. You are putting in the work because you’re brewing beer the right way.

If you don’t want the work, you can always brew in copper. Beer stone isn’t that much of a problem with copper kettles and tanks. But be prepared to deal with other cleaning and sanitation issues. Copper is by no means perfect.