menschmaschine
Well-Known Member
I was re-reading Horst Dornbusch's book called Bavarian Helles and, while I disagree with some of his recommendations (e.g., blanketly doing a 122°F protein rest on all Helles), I found something intriguing in the Appendices for acid rests.
He states that many German Brewers do acid rests (100°F +/- 5°F or 38°C +/- 3°C), even if mash acidity is not a problem. Here are the reasons aside from pH reduction:
-"allows water-soluble grain substances as well as enzymes to begin to hydrolize, which improves the efficiency of enzymatic conversion at subsequent temperature ranges"
-"activation of beta glucanase... breaks down highly viscous, water soluble gums" which, in turn:
..........-"improves extract efficiency during lautering"
..........-"enhances head stability and mouthfeel of the finished beer"
..........-"reduces filter clogging after fermentation"
..........-"prevents chill haze in the bottle"
He also states, "an acid rest has it's greates effect when the mash water is soft."
I'm overall happy with the pale German lagers I make, but I'm always willing to try for improvement. Are all of his statements accurate? (For example, how would it prevent chill haze in the bottle?) Also, why would an acid rest have it's greatest impact when brewing with soft water (keeping in mind that naturally soft water typically has a low pH)?
He states that many German Brewers do acid rests (100°F +/- 5°F or 38°C +/- 3°C), even if mash acidity is not a problem. Here are the reasons aside from pH reduction:
-"allows water-soluble grain substances as well as enzymes to begin to hydrolize, which improves the efficiency of enzymatic conversion at subsequent temperature ranges"
-"activation of beta glucanase... breaks down highly viscous, water soluble gums" which, in turn:
..........-"improves extract efficiency during lautering"
..........-"enhances head stability and mouthfeel of the finished beer"
..........-"reduces filter clogging after fermentation"
..........-"prevents chill haze in the bottle"
He also states, "an acid rest has it's greates effect when the mash water is soft."
I'm overall happy with the pale German lagers I make, but I'm always willing to try for improvement. Are all of his statements accurate? (For example, how would it prevent chill haze in the bottle?) Also, why would an acid rest have it's greatest impact when brewing with soft water (keeping in mind that naturally soft water typically has a low pH)?