Specifically, the following things are believed to positively increase brew house efficiency based on their experiments:
- A mash length of 66 minutes yielded the highest efficiency, with efficiency dropping off above 66 minutes
- Attenuation maxed out at an average mash temperature of 150-151F, but efficiency maxed out around a mash temp of 173F
- Efficiency maxed out at a pH of 5.2
- Efficiency of thinner mashes was higher than thicker, with 2.4 quarts per pound delivering the highest efficiency
With respect to the Zymatic, there is nothing you can really do about thinning the mash. However, there are some things you can do to get more out of your grain bill, depending on what is appropriate for the style of beer you're brewing:
- Increasing the mash time to at least 66 minutes from the usual 60 minutes is an easy way to increase efficiency and gravity without using additional grain, DME, or adjuncts.
- If a sweeter, more full-bodied beer is appropriate for the style being brewed, mashing the grain at a higher temperature will help increase efficiency.
- If a more dry, well-attenuated beer is desired, mashing at 150-151F for 66 minutes should yield a very well-attenuated beer (assuming the yeast strain used for fermentation does its job).
- Checking and adjusting pH to keep it in the 5.2 range will help improve efficiency.
This is all theoretical, but something I can test out in future brews by using the Advanced recipe editor to program in the appropriate times and temperatures. If you don't want to go to that trouble, you may at least want to extend the mash time (especially with the single-step mash option in the recipe editor) to help further convert the grain.