By Susanne Retka Schill | July 15, 2016
The sulfate requirement to meet ASTM specifications has been around since the mid-2000s, and with producers occasionally running into issues meeting those specifications, U.S. Water has been working to reduce the use of sulfur compounds in the process, McCoy says. “Sulfuric acid is used for pH control. There normally is some pH control to make the enzymes work well and to suppress bacterial growth.” The majority of sulfuric acid is used after fermentation. Controlling pH in the beer minimizes mineral deposits that drop out when the beer hits hot heat exchanger plates or in the beer column or in the evaporators. “Plants use sulfuric acid in that case to keep equipment operational by keeping those mineral deposits from forming.” U.S. Water introduced a unique technology several years ago to break up the anionic portion of the minerals before they form deposits, reducing sulfuric acid needs by 60 to 80 percent.
“The reason the chemistry is important is that sulfates, like those you get from sulfuric acid, are nonvolatile, so most of the sulfuric acid that gets used drops out in the coproduct,” McCoy says.