APPENDIX C

The Step Mash (Modified Infusion Mash)

The modified infusion method (step mash, temperature-programmed mash) mimics the traditional decoction-mash sequence, but with less satisfactory results (primarily because no part of the mash is ever boiled). It is, however, far more effective in dealing with undermodified malt than an infusion mash, and a great deal simpler and less time-consuming than a decoction mash, taking only 2 ½ to 5 hours. It has displaced both continental and British tradition in most commercial breweries.

Generally, heat is applied directly to the mash-tun to raise the temperature and to restore temperatures as they fall off during the mash rests. Consequently, a very thick mash can be formed. Caution should be used when applying heat, as rest temperatures can be unwittingly exceeded if not carefully monitored, and if the mash is not constantly and thoroughly mixed.

Crush the malt, dough-in, and bring it to rest at 95 degrees F (35 degrees C), as for decoction mashing. The pH should be near 5.5. After thirty minutes or so, apply heat to the mash-tun to raise the temperature to an even 122 degrees F (50 degrees C) in fifteen minutes; hold it for ten to fifteen minutes. The pH should have dropped to 5.3. Heat to saccharification temperature, quickly for dextrinous worts, or over a span of fifteen to thirty minutes for highly attenuable worts. After fifteen minutes begin testing for starch conversion. When a faint to negative iodine reaction is observed, infuse the mash with boiling water to raise its temperature to 167 to 170 degrees F (75 to 77 degrees C). Hold the temperature and thoroughly mix the mash for five minutes before transferring it to the lauter-tun for sparging.

Step Mash