BIAB Efficiency - need advice on adjusting techniques

Yesterday's brew session yielded what I'm pretty sure is a 94% efficiency. At first I was excited, but after thinking about it, I'm not sure this is ideal. I ended up overshooting the Starting Gravity. So, I'm looking for some advice or thoughts on this process.

I'm using BIAB to mash my grains and I'm limited to a 7-gallon turkey fryer pot. But, I have been able to manage just fine despite the limited kettle size. Here are the numbers for this brew session:

Recipe - Reaper's Mild
5.5 lbs Simpson's Maris Otter Crisp
1.5 lbs C60
.4 lbs (6 oz) Chocolate Malt
Total grain weight - 7.4 lbs

Since I'm doing a 5.5 gallon batch, I could not do a full BIAB due to kettle space limitations. So, here is how I brewed:

Step 1: Mashed the full grain amount in a mesh bag in 6 gallons of water at 158 F for 1.5 hours.

Step 2: heated 1.5 gallons of water to 176 F in a second pot, pulled the wet grain bag out of the 6 gallon mash, drained and dunked it in this second pot for a 10 minute mash at 170 F. Pulled the bag, drained and squeezed.

Step 3: I added the 1.5 gallons of mash-out-wort to the main boil kettle and stirred it all up. I ended up with 6.75 gallons of wort I took a sample for a gravity reading, cooled it to 60 F and it came in at 1.038.

Plugging these grains, wort volume and gravity reading into The Brewer's Friend Brewhouse Efficiency Calculator and into Beersmith, I come up with 94% efficiency! Here is the online calculator I used:

http://www.brewersfriend.com/brewhouse-efficiency/

Step 4: At this point, the wort is all the way to the top of my boil kettle. Too much for this pot to handle! So, I removed one gallon and set it aside. Boiled the rest for 30 minutes to cook off some, then added the gallon back into the pot. Then finished out the boil for one hour following the hop schedule as usual.

I ended up with 5 gallons of wort for pitching at 1.047 Starting Gravity. Reaper's Mild recipe calls for 1.038 SG.

Here are my two questions:

1. How can I adjust this mash method to lower efficiency? Just add water to the final wort before pitching yeast to get a lower SG?

2. I wonder if I can do two beers using this method, sort of like a partigyle? The "main mash" is one beer. Dunking the grains in a second pot of water would yield the second, lower gravity beer. I have not heard of anyone doing this BIAB, but I might experiment with it, to see what happens. The second beer would most likely be a very small volume in yield.

Why a 1.5 hour mash at 158? That seems long for such a warm mash. It probably converted in 30 minutes- a 60 minute mash would have been more than sufficient.

To lower your effiency, you could always add water. Or, if you get 90% consistently, to hit your OG you could just reduce the amount of grain you use.

I almost always hit 72% with my system, so I just adjust all recipes to that efficiency.

I didn't even think about reducing the grain amount - seems pretty obvious and just staring me in the face! I was so focused on the mashing technique, I wasn't thinking about the grain bill.

Well, I have been doing the 90 minute mash, because I read somewhere it is a must for BIAB. Hmmm...thinking I will try a shorter mash next time and see how it goes. Thanks, Yooper, that will save me an hour on brew day!

A bit off topic, but where do you get the mesh bags for BIAB?

You could also adjust your crush, widen your gap a bit and your efficiency will go down. Or just skip the sparge.

The 90 minute mash helps if your mash is very thin, like at 2.5 or 3 qt/lb. That's only if you are using all of your water in the mash and doing no sparge. I don't think it's necessary for your method.

My LHBS sells 24x24 and 24x32 mesh bags. But you can also make them out of polyester voile and nylon thread. Have someone with a sewing machine make a bag out of it, or if you have lots of patience and are a little nuts, you can hand stitch it.

Thanks.

Also, remember that the real importance of efficiency is being able to repeat it with consistency. If you like the beer that you are producing at 94% efficiency, and you can get 94% efficiency batch after batch, then you can repeat THAT process to help recreate your favorite beers over and over.

As everyone already stated, a 60 min. mash is perfectly suitable to an average gravity beer, and that will get your efficiency down. But just remember, the main point of tracking efficiency is it is supposed to be a CONTROL variable that helps you duplicate your process over and over.

Thanks for the replies! This is good information.

I thought I had dialed in with 82% efficiency, as that has been consistent over the last three or four brew sessions. But, when I hit 94% yesterday, it took me off guard. I think the additional ten minute mash at 170 in a second pot is what sent it through the roof.

I plan on buying a larger kettle soon so I can do "true" biab for 5 gallon recipes, using just one pot. Before yesterday, I was doing one-pot BIAB for smaller batches (3 - 3.5 gallons). But, really wanted to do a full 5 gallon recipe so that is why I used the two-pot method.

Still curious about a "BIAB Partigyle" (for lack of a better term) - I may try this on my next brew session.

frailn said:

Thanks for the replies! This is good information.

I thought I had dialed in with 82% efficiency, as that has been consistent over the last three or four brew sessions. But, when I hit 94% yesterday, it took me off guard. I think the additional ten minute mash at 170 in a second pot is what sent it through the roof.

Click to expand...

Referred to as the "mashout", basically this step increases the solubility/thins out the sugars and allows that last little bit of additional extraction. A highly recommended procedure in several BIAB circles and definitely increased my eff when doing full batch no-sparge BIAB brews. YMMV, of course.

frailn said:

Thanks for the replies! This is good information.

I thought I had dialed in with 82% efficiency, as that has been consistent over the last three or four brew sessions. But, when I hit 94% yesterday, it took me off guard. I think the additional ten minute mash at 170 in a second pot is what sent it through the roof.

I plan on buying a larger kettle soon so I can do "true" biab for 5 gallon recipes, using just one pot. Before yesterday, I was doing one-pot BIAB for smaller batches (3 - 3.5 gallons). But, really wanted to do a full 5 gallon recipe so that is why I used the two-pot method.

Still curious about a "BIAB Partigyle" (for lack of a better term) - I may try this on my next brew session.

Click to expand...

A partigyle would work, but it would probably be better to do a larger beer for the first one to make sure you have enough sugar left over for a decent second beer. If you plan for enough volume without having to let the bag drain, then that would help with the partigyle. I think you'd have to wing it for the first couple of batches to see what gravity you end up with on each beer.

thughes said:

Referred to as the "mashout", basically this step increases the solubility/thins out the sugars and allows that last little bit of additional extraction. A highly recommended procedure in several BIAB circles and definitely increased my eff when doing full batch no-sparge BIAB brews. YMMV, of course.

Click to expand...

I knew about this, and should have realized my efficiency would go up. Not sure why I didn't factor it in. I think once I get my larger boil kettle, I will mashout by heating the kettle I'm mashing and boiling in, keeping it to one pot.

I did the second pot mashout because I knew I would need add water to this batch to get it up to 5 gallons, considering my pot is small. I figured, why not double-dunk rather than just adding plain water to the boil. Now I know from experience how mashout impacts the brew efficiency! Up 10%!

thughes said:

Referred to as the "mashout", basically this step increases the solubility/thins out the sugars and allows that last little bit of additional extraction. A highly recommended procedure in several BIAB circles and definitely increased my eff when doing full batch no-sparge BIAB brews. YMMV, of course.

Click to expand...

+1. Mashing out will always improve efficiency.

This is why I love full volume BIAB. I can consistently hit 80% without the need for a second vessel. I really takes all of the guess work out and 80% is my happy #.

John

seabass07 said:

A partigyle would work, but it would probably be better to do a larger beer for the first one to make sure you have enough sugar left over for a decent second beer. If you plan for enough volume without having to let the bag drain, then that would help with the partigyle. I think you'd have to wing it for the first couple of batches to see what gravity you end up with on each beer.

Click to expand...

Thanks! I'm going to experiment with this and see how it goes. Probably do a russian imperial stout for the first beer and a mild for the second beer. What do you think?