I recently moved from a single vessel eBIAB set-up to a 2-vessel set-up with one kettle a standard Mash Tun (MT) with no heating element, and the other my Boil Kettle (BK) that I was using just for boiling. My efficiency numbers were coming in lower than I expected so I set up a small experiment to try different variables I'd read people suggesting in HBT and other areas. I wanted to share my results to try to put some specifics behind the efficiency effects circulating out there. I also have the brew day length in mind, so I somewhat limited myself to a process time limit of no more than 30 minutes from end of mash to the collection of my full pre-boil volume.
For this experiment I went to my LHBS and weighed out equal amounts of grain and put them in their own bags so I knew for sure the weight was exactly what I wanted, and all of the grain came from the same batch.
My MT was a 15-gallon Spike kettle, with Spike's "V3" false bottom and center pickup tube from the center/bottom of the false bottom. I used a Blichmann 120V/2000W RIMS Rocket to control mash temperature.
I adjusted my brew water with my brewing salts to match my "Hop Forward" profile, and then I added Lactic Acid to hit 5.6 pH (measured) on each of the batches. In this small experiment I evaluated different sparge methods as well as grain crush. Measuring pre-boil gravity in the BK, I used BeerSmith mash efficiency calculations for the numbers below.
7 lbs 2-row
1 lb Crystal 40L
0.5 lb White wheat
Mashed @ 1.4 qt/lb for 60 minutes @ 150F
Sparge water @ 168F
Target pre-boil volume 7.5 gallons
Baseline Process
- Time from Mash end to pre-boil volume collected = 20 minutes
- 0.034" grain mill setting
- After mash complete, transferred full sparge water into MT, then pumped wort out of MT to BK.
- Measured mash efficiency = 70.4%
Single Batch Sparge Process
- Time = 23 minutes
- 0.034" grain mill setting
- After mash complete, drained off all wort from MT into BK, added full sparge water volume to MT and stirred, vourlaf, then drained off wort into BK.
- Measured mash efficiency = 75.3%
Single Batch Sparge Process + Finer Crush
- Time = 23 minutes
- 0.026" grain mill setting (had no stuck sparge issues or excessive grain bits in BK)
- After mash complete, drained off all wort from MT into BK, added full sparge water volume to MT and stirred, vourlaf, then drained off wort into BK.
- Measured mash efficiency = 82.7%
20-Minute Fly Sparge Process + Finer Crush
- Time = 28 minutes
- 0.026" grain mill setting (had no stuck sparge issues or excessive grain bits in BK)
- After mash complete, drained off wort until ~2" water level above grain bed, then continually pumped in sparge water while draining to keep water above grain (until sparge water empty).
- Measured mash efficiency = 83.9%
For this experiment I went to my LHBS and weighed out equal amounts of grain and put them in their own bags so I knew for sure the weight was exactly what I wanted, and all of the grain came from the same batch.
My MT was a 15-gallon Spike kettle, with Spike's "V3" false bottom and center pickup tube from the center/bottom of the false bottom. I used a Blichmann 120V/2000W RIMS Rocket to control mash temperature.
I adjusted my brew water with my brewing salts to match my "Hop Forward" profile, and then I added Lactic Acid to hit 5.6 pH (measured) on each of the batches. In this small experiment I evaluated different sparge methods as well as grain crush. Measuring pre-boil gravity in the BK, I used BeerSmith mash efficiency calculations for the numbers below.
7 lbs 2-row
1 lb Crystal 40L
0.5 lb White wheat
Mashed @ 1.4 qt/lb for 60 minutes @ 150F
Sparge water @ 168F
Target pre-boil volume 7.5 gallons
Baseline Process
- Time from Mash end to pre-boil volume collected = 20 minutes
- 0.034" grain mill setting
- After mash complete, transferred full sparge water into MT, then pumped wort out of MT to BK.
- Measured mash efficiency = 70.4%
Single Batch Sparge Process
- Time = 23 minutes
- 0.034" grain mill setting
- After mash complete, drained off all wort from MT into BK, added full sparge water volume to MT and stirred, vourlaf, then drained off wort into BK.
- Measured mash efficiency = 75.3%
Single Batch Sparge Process + Finer Crush
- Time = 23 minutes
- 0.026" grain mill setting (had no stuck sparge issues or excessive grain bits in BK)
- After mash complete, drained off all wort from MT into BK, added full sparge water volume to MT and stirred, vourlaf, then drained off wort into BK.
- Measured mash efficiency = 82.7%
20-Minute Fly Sparge Process + Finer Crush
- Time = 28 minutes
- 0.026" grain mill setting (had no stuck sparge issues or excessive grain bits in BK)
- After mash complete, drained off wort until ~2" water level above grain bed, then continually pumped in sparge water while draining to keep water above grain (until sparge water empty).
- Measured mash efficiency = 83.9%