Regardless of the scale of operation, careful consideration must go into choosing the correct equipment and materials for your brewing system. Flavor can be affected by the slightest variables, be it the type of tubing or ball valves you use. Materials of construction matters, and while brass and stainless steel ball valves for brewing have the same design, their chemical differences can ultimately influence the quality of your brew.
Chemistry 101: Brass versus Stainless Steel
Both brass and stainless steel are alloys, or mixtures, of various metals. Brass usually contains mostly copper and zinc with a small percentage of lead while stainless steel contains iron, chromium and nickel. Iron by itself rusts. However, when mixed with chromium and nickel, the iron-chromium- nickel alloy becomes highly resistant to corrosion. Likewise, copper is a soft metal and zinc is brittle. Together, they form brass, a strong and malleable alloy.
Being metals, both brass and stainless steel react with acids and alkaline solutions. bases. However, stainless steel has considerably higher resistance and does not react with weak acids and most alkaline solutions. Brass suffers from a process called dezincification when zinc is leached out of the alloy. Ammonia can also have an adverse effect on brass and cause cracks in the metal.
Your Best Bet for Brewing
Generally speaking, stainless steel ball valves have an edge over brass because of stainless steel's superior resistance to acids, cleaning solvents and normal wear. When brass corrodes, it releases substances. Even in low quantities, lead in brass can contaminate water. As a result, no brass should be used anywhere in plumbing that contacts food, beverage or even water. For brewing, stainless steel ball valves are by far the safer choice since they do not contain any lead and do not corrode.
If you are brewing at home or on a commercial scale, you may be well aware that the least bit of contamination in your system can affect the taste and ruin the batch. Bacteria and organic buildup can also sour and foul your product. A system that can be thoroughly cleaned combats this problem and should be regularly maintained.
Stainless steel is much more resistant to corrosion caused by weak acids and alkaline solutions that are typically the active ingredients in cleaning solvents. Brass, also reacts with ammonia products. As you clean and flush out your system, you do not want to create any points of weakness, which will occur if you have brass in the system.
Even if brass were lead-free, it presents other weaknesses that stainless steel eliminates. Your best bet is to use stainless steel ball valves for brewing to reduce unwelcome flavors.