[Lazy Ant Brewing]

I'm a novice at this.  I've been doing all-grain BIAB on darker beers with OG from 1.040 to 1.060.  I run my grain through the mill twice for a finer crush to improve efficiency.

I'd often wondered about the water to grain ratios being thinner for BIAB.  I'm going to try Denny's idea of mashing at 1.75 to 2 qts/ lb and then topping up to boil volume.

Thanks

[erockrph]

I'm a novice at this.  I've been doing all-grain BIAB on darker beers with OG from 1.040 to 1.060.  I run my grain through the mill twice for a finer crush to improve efficiency.

I'd often wondered about the water to grain ratios being thinner for BIAB.  I'm going to try Denny's idea of mashing at 1.75 to 2 qts/ lb and then topping up to boil volume.

I go up to the low 3's qt/lb using a hybrid BIAB/no-sparge method without an issue. I start to run into issues with decreases in efficiency as I get closer to 4qt/lb, so I've started using Denny's top-off method for session beers where the mash would be extra-thin.

I can't say that I check my pH's religiously, but I spot-checked several recipes when I started brewing AG using this technique and everything was always within range of what I was expecting based on Brun'water and Kai's calculator on Brewer's Friend.

[charles1968]

I'm a novice at this.  I've been doing all-grain BIAB on darker beers with OG from 1.040 to 1.060.  I run my grain through the mill twice for a finer crush to improve efficiency.

I'd often wondered about the water to grain ratios being thinner for BIAB.  I'm going to try Denny's idea of mashing at 1.75 to 2 qts/ lb and then topping up to boil volume.

I go up to the low 3's qt/lb using a hybrid BIAB/no-sparge method without an issue. I start to run into issues with decreases in efficiency as I get closer to 4qt/lb, so I've started using Denny's top-off method for session beers where the mash would be extra-thin.

I can't say that I check my pH's religiously, but I spot-checked several recipes when I started brewing AG using this technique and everything was always within range of what I was expecting based on Brun'water and Kai's calculator on Brewer's Friend.

You should get better efficiency from a thinner mash rather than lower efficiency:
http://braukaiser.com/wiki/index.php?title=Effects_of_mash_parameters_on_fermentability_and_efficiency_in_single_infusion_mashing#Mash_thickness

"The brewhouse efficiency of the tick mashes remained almost constant between 58 and 60% over the temperature range of the experiments, but the brewhouse efficiency for the thinner mash showed a strong dependency on the temperature and was always better than the efficiency of the tick mash. That leads to the conclusion that thinner mashes perform better and allow for better extraction of the grain. Briggs also reports that thinner mashes can convert more starch but that most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg [Briggs, 2004] "

[erockrph]

I'm a novice at this.  I've been doing all-grain BIAB on darker beers with OG from 1.040 to 1.060.  I run my grain through the mill twice for a finer crush to improve efficiency.

I'd often wondered about the water to grain ratios being thinner for BIAB.  I'm going to try Denny's idea of mashing at 1.75 to 2 qts/ lb and then topping up to boil volume.

I go up to the low 3's qt/lb using a hybrid BIAB/no-sparge method without an issue. I start to run into issues with decreases in efficiency as I get closer to 4qt/lb, so I've started using Denny's top-off method for session beers where the mash would be extra-thin.

I can't say that I check my pH's religiously, but I spot-checked several recipes when I started brewing AG using this technique and everything was always within range of what I was expecting based on Brun'water and Kai's calculator on Brewer's Friend.

You should get better efficiency from a thinner mash rather than lower efficiency:
http://braukaiser.com/wiki/index.php?title=Effects_of_mash_parameters_on_fermentability_and_efficiency_in_single_infusion_mashing#Mash_thickness

"The brewhouse efficiency of the tick mashes remained almost constant between 58 and 60% over the temperature range of the experiments, but the brewhouse efficiency for the thinner mash showed a strong dependency on the temperature and was always better than the efficiency of the tick mash. That leads to the conclusion that thinner mashes perform better and allow for better extraction of the grain. Briggs also reports that thinner mashes can convert more starch but that most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg [Briggs, 2004] "

Interesting information there. In the past, I increased the duration of my mash on the thinner batches and that brought their efficiency in line with the thicker ones, so I'm pretty sure I didn't max out the absolute efficiency possible at 4 qt/lb.

I prefer the top-off method now for session beers because I pre-heat my topoff water in the kettle and runoff into it. That saves me some time on the way to boil, and kind of does some of the function of a mashout for batches where I want to lock in the dextrin profile instead of having some ongoing conversion as I start heating my wort to boil.

[Lazy Ant Brewing]

"The brewhouse efficiency of the tick mashes remained almost constant between 58 and 60% over the temperature range of the experiments, but the brewhouse efficiency for the thinner mash showed a strong dependency on the temperature and was always better than the efficiency of the tick mash. That leads to the conclusion that thinner mashes perform better and allow for better extraction of the grain. Briggs also reports that thinner mashes can convert more starch but that most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg [Briggs, 2004] "

Isn't 2.5 l/kg about equivalent to 1.2 qts/lb?  How is that thinner than say 2 qts/lb. mentioned in previous posts above?  I'm confused.

[erockrph]

"The brewhouse efficiency of the tick mashes remained almost constant between 58 and 60% over the temperature range of the experiments, but the brewhouse efficiency for the thinner mash showed a strong dependency on the temperature and was always better than the efficiency of the tick mash. That leads to the conclusion that thinner mashes perform better and allow for better extraction of the grain. Briggs also reports that thinner mashes can convert more starch but that most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg [Briggs, 2004] "

Isn't 2.5 l/kg about equivalent to 1.2 qts/lb?  How is that thinner than say 2 qts/lb. mentioned in previous posts above?  I'm confused.

Good catch. Leave it to the metric folk to screw up a good thing 

[charles1968]

Isn't 2.5 l/kg about equivalent to 1.2 qts/lb?  How is that thinner than say 2 qts/lb. mentioned in previous posts above?  I'm confused.

Good question. If you look at the graph of Troester's results, he gets maximum efficiency at 5 l/kg, but 2.5 l/kg is nearly all the way there (hence "most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg").

The main point is that efficiency doesn't fall off as the mash gets thinner.

I'll post an image of the graph when I get to a computer...

[charles1968]

[denny]

The main point is that efficiency doesn't fall off as the mash gets thinner.

My efficiency went up about 3-5 pts. when I switched from 1.25 to 1.75 qt./lb.

[HoosierBrew]

My efficiency went up about 3-5 pts. when I switched from 1.25 to 1.75 qt./lb.

Same here.

[charles1968]

The main point is that efficiency doesn't fall off as the mash gets thinner.

My efficiency went up about 3-5 pts. when I switched from 1.25 to 1.75 qt./lb.

You could probably nudge it up a bit more if you go even thinner.

[denny]

The main point is that efficiency doesn't fall off as the mash gets thinner.

My efficiency went up about 3-5 pts. when I switched from 1.25 to 1.75 qt./lb.

You could probably nudge it up a bit more if you go even thinner.

It's at 83% now.  I really don't care much if it's higher.  I didn't take any measures to get higher efficiency...it just happened when I made a few changes.

[erockrph]

Isn't 2.5 l/kg about equivalent to 1.2 qts/lb?  How is that thinner than say 2 qts/lb. mentioned in previous posts above?  I'm confused.

Good question. If you look at the graph of Troester's results, he gets maximum efficiency at 5 l/kg, but 2.5 l/kg is nearly all the way there (hence "most of the conversion potential is reached at a water to grist ratio of 2.5 l/kg").

The main point is that efficiency doesn't fall off as the mash gets thinner.

I'll post an image of the graph when I get to a computer...

5L/kg is still a lot thicker than many full-volume/no-sparge mashes (such as BIAB) would be. Mash thicknesses in the range of 3-4 qt/lb (or more) are pretty common for low-to-moderate gravity beers. I can't imagine that the trend of increasing efficiency as mash thickness decreases continues on forever. At some point the concentrations of malt and enzymes have to dip low enough where you convert less starch within a given mash length than thicker mashes.

Having said that, I feel pretty comfortable that this point is thinner than 3 qt/lb, and possibly well beyond that.

[charles1968]

I can't imagine that the trend of increasing efficiency as mash thickness decreases continues on forever.

It probably levels off somewhere close to 5 l/kg (2.4 qt/lb). If there was significant extra efficiency above that, commercial brewers would be doing it, but as far as I know 5 l/kg is as high as they go (most often for pilsners).

At some point the concentrations of malt and enzymes have to dip low enough where you convert less starch within a given mash length than thicker mashes.

Yes reaction rate will drop with dilution, but as along as you allow enough time for conversion it won't affect efficiency. I've read that all conversion happens in the first 15 mins of a normal mash but I don't believe that myself as my overnight mashes are always more efficient than one hour.