Hello
We are a 10 BBL brewery using Dutsche Beverage Technology brewhouse and a local (French) mill + screw auger (from Criquet). Mill is a 2 rollers crushing up to 1T / h
We only have ~6 months of operation and ~20 batches under our belt.
A consistent issue is a very slow transfer {2 to 2.5 hours or more}. We have had 2 fully stuck mashes and we are trying to solve the issue. We have been using ~150 liters of rice hulls per brew to help. Which it does a bit but it didn't keep us from a fully stuck mash on our last IPA (6.9% ABV)
Looking at the grist out of the mill I feel like the flour quantity is somewhat greater than I am used to from previous brewing experience.
We performed some analysis on the grist with lab calibrated sieves.
One finding from adjusting the rollers was that the rollers are not perfectly flat. This will explain (potentially) some findings below.
With the mill supplier we did several tests with difference mill gap. At ~1mm to 1.2mm (rollers are not flat so we have sections at 1mm apart and sections at 1.2mm apart) we have the following:
74 % captured by the 1mm sieve
12 % captured by the 0.55 mm sieve
14% passing through the 0.55 mm sieve (of which we have 50-50 > than 0.25 mm and < than 0.25 mm)
We did the analysis on a sample size of 9.32 KG {20.55 lbs} which we collected from the screw auger after travelling the entire way.
We had some grain not crushed in the 74% captured by the 1mm sieve but not enough to be alarming
Online research were not super fruitful - only finding this: beerandwinejournal.com/malt-sieves/ {Thanks Alex L.!}
From the brewing elements series - Malt written by John Mallet we don't have any defined grist analysis. And yes, we get it - target grist depend on the brewhouse / malt / recipe / etc... - but guidelines can be useful!
During mash we have our rakes going in alternate directions at 40% of the speed. We vorlauf during temp. increase (when we can) to have a more accurate temp reading in the MLT.
Why do we have slow transfer and stuck mash?
Any guidance you may have regarding:
- process to avoid stuck mash
- grist analysis
- material to read
- feedback
Thanks
Matt
We are a 10 BBL brewery using Dutsche Beverage Technology brewhouse and a local (French) mill + screw auger (from Criquet). Mill is a 2 rollers crushing up to 1T / h
We only have ~6 months of operation and ~20 batches under our belt.
A consistent issue is a very slow transfer {2 to 2.5 hours or more}. We have had 2 fully stuck mashes and we are trying to solve the issue. We have been using ~150 liters of rice hulls per brew to help. Which it does a bit but it didn't keep us from a fully stuck mash on our last IPA (6.9% ABV)
Looking at the grist out of the mill I feel like the flour quantity is somewhat greater than I am used to from previous brewing experience.
We performed some analysis on the grist with lab calibrated sieves.
One finding from adjusting the rollers was that the rollers are not perfectly flat. This will explain (potentially) some findings below.
With the mill supplier we did several tests with difference mill gap. At ~1mm to 1.2mm (rollers are not flat so we have sections at 1mm apart and sections at 1.2mm apart) we have the following:
74 % captured by the 1mm sieve
12 % captured by the 0.55 mm sieve
14% passing through the 0.55 mm sieve (of which we have 50-50 > than 0.25 mm and < than 0.25 mm)
We did the analysis on a sample size of 9.32 KG {20.55 lbs} which we collected from the screw auger after travelling the entire way.
We had some grain not crushed in the 74% captured by the 1mm sieve but not enough to be alarming
Online research were not super fruitful - only finding this: beerandwinejournal.com/malt-sieves/ {Thanks Alex L.!}
From the brewing elements series - Malt written by John Mallet we don't have any defined grist analysis. And yes, we get it - target grist depend on the brewhouse / malt / recipe / etc... - but guidelines can be useful!
During mash we have our rakes going in alternate directions at 40% of the speed. We vorlauf during temp. increase (when we can) to have a more accurate temp reading in the MLT.
Why do we have slow transfer and stuck mash?
Any guidance you may have regarding:
- process to avoid stuck mash
- grist analysis
- material to read
- feedback
Thanks
Matt
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