Brewtips - All Grain
Mash Yield Experiment
The following experimental mashes were conducted to determine the effects on extract efficiency in an infusion mash with the following options:
- 30 minute rest at 105F 'beta-glucanase/liquification of amylases'
- 15 minute rest at 165-170F 'Mash-out'
The following conditions were used for all experiments:
- Softened carbonate well water boiled 20 min. with 1.5 tsp. CaSO4 / 5 gal. to reduce carbonate/bicarbonate hardness. Used for mash and sparge.
- HDM Belgian Pale Ale malt - 2# grist per mash crushed w/ fixed roller JSP grain mill
- Total mash water = 1.25qts./lb. grist
- Sparge water = 165-170F / 1.4-1.5qts./lb. grist
- Total sweet wort runoff = 5-6qts. (2.5-3.0 qts./lb.)
- Sparge time = 10 min. to gather 5-6qts. runoff
- Lautering/Sparging conducted in 5gal. Gott cooler w/ false bottom
- Mash pH 5.3 - 5.5
- Mash-in @ 155F - hold for 60 min. 'One-Step Infusion' extract efficiency = 55% = 1.024 s.g./lb. in 1 gal.
- Mash-in @ 155F - hold for 60 min - boost to 165-170 F - hold 15 min. grist doughed in at mash water rate of 1.25 qts./lb. grist - external heat boost to 165-170F 'Step Infusion_MO' extract efficiency = 64% = 1.028 s.g./lb. in 1 gal.
- Mash-in @ 105F (0.75 qts. water/lb. grist) - hold 30 min. - boiling water boost (0.5 qt./lb. grist) + external heat to 155F - hold 60 min. 'Step Infusion_BG' extract efficiency = 68% = 1.030 s.g./lb. in 1 gal.
- Mash-in @ 105F (0.75 qts. water/lb. grist) - hold 30 min. - boiling water boost (0.5 qt./lb. grist) + external heat to 155F - hold 60 min. external heat infusion to 165-170F - hold 15 min. 'Step Infusion_BG_MO' extract efficiency = 71% = 1.031 s.g./lb. in 1 gal.
Conclusions: Yield Experiment
- In this experiment, a 30 min. rest at 105F was more effective in increasing yield than a 15 min. 165-170F mashout rest.
- In this experiment, when a 30 min. rest at 105F was employed, only a minor increase in yield was obtained with a 15 min. 165-170F mashout rest.
Fermentability Experiment
Several experimental mashes were conducted to evaluate the effects on fermentability of 140F/40C rests of 0 min, 15 min., and 30 min. using a 40/60/70/75 mash program. Details of this experiment are as follows:
- Mash conditions from Extract Efficiency experiment were used
- A large amount of M&F dried yeast (2 grams /qt.) was pitched to insure complete fermentation
- 20 oz. experimental worts were fermented for 3 days at 66-68F in Korbel (squat) champagne bottles.
Worts from the following three mashes were fermented:
Mash Rest Temp
Fermentability 105F/40C 140F/60C 158F/70C 167F/75C
High 30 min. 30 min. 30 min. 15 min.
Medium 30 min. 15 min. 45 min. 15 min
Low 30 min. - 50 min. 15 min
Fermentation results are summarized below:
Fementability Original Gravity Final Gravity Apparent Attenuation
High 1.052 1.017 67%
Medium 1.054 1.019 65%
Low 1.050 1.019 62%
Conclusions: Fermentability Experiment
- Apparent attenuation trend matched expectations.
- Apparent attenuation could be further increased by a 45-60 min. rest at 140F prior to the boost to 158F.
- Apparent attenuation can be decreased through the addition of specialty malts such as dextrin or crystal malt.
Rob Reed
