Low efficiency BIAB

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CanAusBrewer

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I just brewed a DIPA yesterday as a partial mash BIAB and had surprisingly low efficiency. I mashed 4.2 kg of grain in a 15.2 l pot which was filled to the rim with grain and mash water. The mash was still very wet with no dough balls and I regularly stirred it. I mashed at 67 C with a 75 C mashout for 60 minutes. I then hung the bag over the kettle and sparged with 4 litres of 75 C water in a watering can.

I boiled and added a couple litres of boiling water during the boil to account for evaporation so hop attenuation would not be reduced and added 1.5 kg light LME at 5 mins left in the boil. I then cooled for a 20 min hop stand at 75 C and cooled to 24 deg, poured through muslin, squeezed the wort from the hops in the bag and topped up to 19 l with cold tap water and checked OG which was 1.058. I ended up draining some of the wort from the tap and re-boiling with 800 g DME to get it back up to 1.070 where it was supposed to be.

I have used this brewing method before with 3 kg of grain and achieved 82% efficiency so I am really not sure what went wrong. Any thoughts? Was it too much grain in that pot for an efficient mash?
 
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CanAusBrewer

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Could it be that the wort I was aiming for was too concentrated? Would ibebetteroff doing more LME and less grain on my bigger beers? I was hoping this method would allow me to make full AG BIAB batches by making an over-concentrated wort and topping up to 19 litres to dilute.
 

cheesehed007

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Could it be your top off water wasn't mixed well with the wort when you took your reading?


Sent from my van, down by the river.
 
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CanAusBrewer

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Could it be your top off water wasn't mixed well with the wort when you took your reading?


Sent from my van, down by the river.
I thought about that but seriously doubt it. I stirred the **** out of it to aerate before taking my sample.
 

pricelessbrewing

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In the future, I would get og before dilution then just do some simple math to determine how much water is needed.
 

Peruvian802

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Approximately 9.25lbs of grain in a 4 gallon pot? It seems like it must have been a very thick mash. Maybe that effected efficiency.

However, I'd agree that sparging and then adding water without knowing what your gravity was more to blame.
 
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CanAusBrewer

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Approximately 9.25lbs of grain in a 4 gallon pot? It seems like it must have been a very thick mash. Maybe that effected efficiency.

However, I'd agree that sparging and then adding water without knowing what your gravity was more to blame.
Yes it was way thicker than any mash I have done so next time I think for the big beers I will need to either double up on my LME and use 2 cans instead of one and make up the remainder with grain or I need to find a bigger pot.
 
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