Brewed today. 50 gal batch rye stout. 1st 62 gal of mash runnings came out at 1080. The next 10 L of running came out at 1034 ( added mid boil to avoid boil over). The last 5L of running came out at 1044?! Why was the last 5L higher than the 10L pull? Any insight is appreciated.
Gravity of Mash runnings
- Thread starter Hopblock
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I don't understand. The second runnings were 10L but the third runnings were 5L?
If that's the case, the 10L was more diluted.
If that's the case, the 10L was more diluted.
Because one had 10L of water, and one had 5L of water?
^ This........
GNBrews said:
The grain bed was not moved or touched. Flowrate was not changed because no more hot water was added and the valve remained opened at a constant angle. The mash water just drained out via gravity, and the very last 5L to trickle out happened to have a higher gravity than the 10L preceding it. I'm stumped as to why.
Ah, I thought you did it in two batch sparges. You must have had some channeling or something. Did you keep a couple of inches of water over the grain bed the entire time?
Yes, while the boil kettle was filling up. Around 42 gal I stopped introducing water to the mash and just let it drain through with the goal of filling the kettle to 62 gal and catching 10 L of runnings as the last drop of water came out of the mash tun. This brew we almost did this but after catching 10L there was 5L more than expected at the very end. I would think the runnings at this point would be almost water, thus my question...why were these runnings higher in gravity than the 10L just preceding it?
GNBrews
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My guess would be stratification. The water at the top of the mash tun (the last 5L) was hotter than the water at the bottom (10L) that flowed out first. The hotter water extracted sugars more efficiently. It's all really a guessing game since we didn't watch your process.
Kaiser
Well-Known Member
yes, you must have had some stratification and channeling to change the wort gravity in that way.
Kai
Kai
Agreed on stratifiaction. I switched from a herms to a stirator in the mash tun and my efficiency dropped 10 points. Then I figured it out that the stirrator left in the mash during sparge was causing channeling. So I now remove the stirator before sparging and get a 10 point increase in efficency over the herms system.
