Gelatinization Temperatures for Adjuncts

Posted to HBD #2092, 7/9/96,
by Rob Lauriston, robtrisch@mindlink.bc.ca

Gelatinization of barley starch has been mentioned recently, and people periodically ask about how to treat adjuncts. The following is from "Malting, Wort Production and Fermentation", which is volume 2 in "An Introduction to Brewing Science and Technology (Series II)" from The Institute of Brewing.


Gelatinization temperatures of starches
_______________________________________

starches                        gelatinization temperatures 'C

maize                                      70-75
sorghum                                    70-75
rice                                       68-75
wheat                                      52-54
barley                                     61-62
potato                                     56-69

"[The table...] illustrates why some adjuncts are cooked and others are not. Since starch conversion in the mash tun occurs most efficiently at about 63-65'C, those starches which gelatinize above 65'C would yield little extract if they were not heated beyond 65'C (or cooked) to ensure general liquifaction. Maize, rice or sorghum grits are usually cooked with 5% malt (or heat-stable alpha-amylases) to keep the cooked grits in a liquid form. The cooked grits are then transferred to the mash mixture for conversion. The alpha-amylase of the malt is responsible for the liquefaction during cooking." pp.50-51.