Learning small scale biab

[Beerhog]

So after many extract brews I moved to partial biab method. I`m still new to this style of brewing and I got some questions. Normally I mash the grain than hoist the bag, let it drain and than put it on collander for sparging. I just had a thought, what if instead of sparging I would take the whole grain bag and dump it into sparge water and wash the grain in sparge water?
Would the mash efficiency be improved by any significant amount? All Biab guides I read don't even sparge, but this seems like a waste of sugars to me. Also, how big of a pot would i need to upgrade to be able to brew virtually any 5 gal batch recipe? Let's say any recipe up to 1.065 OG pure all grain? I'm slowly testing the limits of my 5 gal stock pot and got to mash 7.5 lbs of grain in it, and with about 1 lb of table sugar i can make 5 gals of 1.050 wort.

 

[DBhomebrew]

You're taking about a dunk sparge, essentially a BIAB batch sparge.

I drop my mashed and drained bag into a bucket of room temp sparge water, open the bag, give a good stir, then close it up, pull and drain. Less mess and much better efficiency than when I tried a pour over.

 

[DBhomebrew]

I'm slowly testing the limits of my 5 gal stock pot

I recently made a batch 3.5gal into the fermenter at 1.094. 100% malt, 13.25lb, 72% efficiency, dunk sparge, 2hr boil. Pre-boil was 4.5gal. It required a very watchful eye and finesse with the gas as it came close to boil.

https://www.homebrewtalk.com/threads/what-i-did-for-beer-today.294038/post-9021823

 

[doug293cz]

So after many extract brews I moved to partial biab method. I`m still new to this style of brewing and I got some questions. Normally I mash the grain than hoist the bag, let it drain and than put it on collander for sparging. I just had a thought, what if instead of sparging I would take the whole grain bag and dump it into sparge water and wash the grain in sparge water?
Would the mash efficiency be improved by any significant amount? All Biab guides I read don't even sparge, but this seems like a waste of sugars to me. Also, how big of a pot would i need to upgrade to be able to brew virtually any 5 gal batch recipe? Let's say any recipe up to 1.065 OG pure all grain? I'm slowly testing the limits of my 5 gal stock pot and got to mash 7.5 lbs of grain in it, and with about 1 lb of table sugar i can make 5 gals of 1.050 wort.

Yes, sparging will increase your mash efficiency, specifically the lauter efficiency component. Mash efficiency = conversion efficiency * lauter efficiency. A single batch (dunk) sparge will increase your lauter efficiency about 8 percentage points vs. a no sparge lauter, all else (grain absorption rate, pre-boil volume, conversion efficiency, etc.) being equal. See the chart below:

A pour over sparge is more similar to fly sparging than batch sparging, but harder to get consistent results with than a fly sparge in a well designed MLT. Consistency is what you want in order to have a predictable process.

Brew on

 

[Beerhog]

I recently made a batch 3.5gal into the fermenter at 1.094. 100% malt, 13.25lb, 72% efficiency, dunk sparge, 2hr boil. Pre-boil was 4.5gal. It required a very watchful eye and finesse with the gas as it came close to boil.

https://www.homebrewtalk.com/threads/what-i-did-for-beer-today.294038/post-9021823

If I'm reading correctly you were able to mash 13.25lb of grain in 5 gallon stock pot? If that's the case i may not need to upscale my brew kettle for my needs

 

[Beerhog]

Yes, sparging will increase your mash efficiency, specifically the lauter efficiency component. Mash efficiency = conversion efficiency * lauter efficiency. A single batch (dunk) sparge will increase your lauter efficiency about 8 percentage points vs. a no sparge lauter, all else (grain absorption rate, pre-boil volume, conversion efficiency, etc.) See the chart below:

View attachment 711405

A pour over sparge is more similar to fly sparging than batch sparging, but harder to get consistent results with than a fly sparge in a well designed MLT. Consistency is what you want in order to have a predictable process.

Brew on

Whoa, that's a lot more technical data than I even comprehend at this time. But to keep it simple, what is the highest efficiency I can expect from biab? I know there are many efficiencies but I'm more concerned with how much ppg I can squeeze out of pound of grain. I'm not sure but this is referred to as mash efficiency. Usually guides say to use 75% as starting figure. So for example , 2-row barley yields 37 max ppg but with 75% mash efficiency it will yield me 27.75 ppg. Can I expect something higher than 75%?

 

[DBhomebrew]

If I'm reading correctly you were able to mash 13.25lb of grain in 5 gallon stock pot? If that's the case i may not need to upscale my brew kettle for my needs

Yep, 5gal stock pot. Pictures in that link show it at mash and top of boil.

13.25lb grain, pretty well pulverized
Total Water 5.51
Strike 3.34
Sparge 2.18
1st Running 2.20
2nd Running 2.25
Pre-Boil 4.45 @ 1.080
Post-Boil 3.73 @ 1.094
Into Fermenter 3.40

ETA: Just to be clear, my experiences show you CAN get this volume output from a 5G kettle, but you are very much risking a boil over. I keep an extremely close eye on it with one hand on the gas knob, the other on a spray bottle to knock the foam down if needed. That said, unless you're looking for imperial-range OGs, the pre-boil vol is your bottleneck.

 

[DBhomebrew]

Can I expect something higher than 75%?

I'm going to let the more experienced members guide you toward deeper understanding of efficiencies, but with my setup as described...

Mash efficiencies for my two previous batches (very close in post-boil vol, ~3.7G) were 70%@1.094 OG, 82%@1.043.

ETA: Moved to the relevant post above.

 

[Beerhog]

Yep, 5gal stock pot. Pictures in that link show it at mash and top of boil.

13.25lb grain, pretty well pulverized
Total Water 5.51
Strike 3.34
Sparge 2.18
1st Running 2.20
2nd Running 2.25
Pre-Boil 4.45 @ 1.080
Post-Boil 3.73 @ 1.094
Into Fermenter 3.40

ETA: Just to be clear, my experiences show you CAN get this volume output from a 5G kettle, but you are very much risking a boil over. I keep an extremely close eye on it with one hand on the gas knob, the other on a spray bottle to knock the foam down if needed. That said, unless you're looking for imperial-range OGs, the pre-boil vol is your bottleneck.

Awesome! Thank you for in-depth explanation. I guess basic 5 gal stock pot is a very potent brewing tool!

 

[DBhomebrew]

Awesome! Thank you for in-depth explanation. I guess basic 5 gal stock pot is a very potent brewing tool!

For me, it's the right tool for the job. I don't drink all that much so I don't need full 5 or 10G batches, it was already in the kitchen inventory, it fits on the stove and in the kitchen sink, etc etc.

 

[doug293cz]

Whoa, that's a lot more technical data than I even comprehend at this time. But to keep it simple, what is the highest efficiency I can expect from biab? I know there are many efficiencies but I'm more concerned with how much ppg I can squeeze out of pound of grain. I'm not sure but this is referred to as mash efficiency. Usually guides say to use 75% as starting figure. So for example , 2-row barley yields 37 max ppg but with 75% mash efficiency it will yield me 27.75 ppg. Can I expect something higher than 75%?

It's possible to get 80+% mash efficiency for no-sparge BIAB for relatively low gravity beers. As the target OG increases, more grain is required, and this causes lauter efficiency (and mash efficiency) to decrease, unless you increase the pre-boil volume to compensate for the higher fraction of the wort lost to grain absorption. To get the same lauter/mash efficiency with 15 lb vs. 7.5 lb of grain, you would have to double the pre-boil volume (keep the grain weight to pre-boil volume ratio constant.)

If you do a single dunk sparge, you can get 90+% lauter/mash efficiency for lower OG beers. The same decreasing efficiency with increasing grain weight applies when you sparge, just like no-sparge.

Very often the controlling factor with poor mash efficiency is low conversion efficiency. At 100% conversion efficiency, your mash efficiency will equal your lauter efficiency (thus your mash efficiency can never exceed the efficiencies shown on the above chart.) If your conversion is less than 100%, then your mash efficiency will be lower than your lauter efficiency - sometimes by a lot. The most frequent cause of poor conversion efficiency is too coarse a grain crush. This is because larger grits take longer to convert compared to smaller grits. Longer mash times can (at least partially) compensate for larger grits (coarser crush.) You can measure your conversion efficiency with the method here (the mash should be well stirred prior to taking the sample.) If the conversion % is too low for your liking, you can extend your mash to get more conversion.

Brew on

 

[kmarkstevens]

For what it's worth, I tried dunk sparge and got at least 10 percentage point uptick in efficiency. Without checking notes, I went from about 65% (pour over a colander) to 75% (dunk sparge).

 

[gmagee]

*somewhat off topic*

If you do a single dunk sparge, you can get 90+% lauter/mash efficiency for lower OG beers. The same decreasing efficiency with increasing grain weight applies when you sparge, just like no-sparge.

Do you think recirculating, as opposed to dunk sparging, can have a similar impact on efficiency?

 

[McKnuckle]

Doug will give a solidly science-based answer to that question, but think of it this way:

If you take a bath in a whirlpool tub and turn on the jets to recirculate the water, at some point all the dirt that's going to come off readily will be in the water, which just continues to move through the pipes and back into the bath.

However, if you get out of that tub and step into a second bathtub filled with clean water, it will rinse some additional surface dirt from your body.

The dunk sparge is about lautering, or rinsing efficiency. You don't rinse anything if there's no sparge at all. You only get the results of the initial soak (mash).

 

[doug293cz]

*somewhat off topic*



Do you think recirculating, as opposed to dunk sparging, can have a similar impact on efficiency?

@McKnuckle 's analogy is a good one.

Recirculating might speed up your conversion a little, and if your mash time wasn't already long enough to get 100% conversion, your conversion efficiency might increase. This will increase your mash efficiency, but not your lauter efficiency.

There are some cases where recirculation can improve lauter efficiency: Mashing configurations that have liquid outside of the grain mass will often have serious sugar concentration gradients between the grain mass wort and the outside wort, with the wort in the grain mass having higher sugar concentration. If you drain the mash without homogenizing the wort throughout it's entire volume, then the wort absorbed by the grain (the wort you don't collect) will have a higher than average sugar concentration, thus lowering lauter efficiency. Recirculation (and stirring also) are effective ways to homogenize the wort, thus leading to somewhat higher lauter efficiency.

In mashing systems with solid sided baskets (aka malt pipes), wort in the vertical space between the basket and vessel wall does not participate in recirculation (unless special steps are taken), thus recirculation (or stirring) does not effectively homogenize the wort, and lauter efficiency suffers.

Brew on

 

[madscientist451]

Also, how big of a pot would i need to upgrade to be able to brew virtually any 5 gal batch recipe?

You need to account for evaporation and leaving some kettle trub behind when you dump to the fermenter, so 5 gallons of wort + 1 gallon evaporation + 1/2 gallon kettle trub = 6.5 gallons. Then you need some extra room so you don't have a boil over, so a 7.5 gallon pot will work fine.
I BIAB with a 7.5 gallon brew pot and use a cheapo 4 gallon side pot for the dunk sparge. I'll use two burners on the stove to get them both boiling faster, the small one gets up to temp faster, so I carefully transfer some of the hot wort to the bigger pot, eventually they are both combined.
The mash equation is a little trickier, but there are mash volume calculators available to figure it out.
I Unusually start with about 7.5 gallons of water (your number will vary depending on evaporation and how much grain in the recipe) and have about 5 gallons in the big pot for the mash and 2.5 gallons in the small pot for the dunk sparge.
After you run a few batches, you'll figure out a method and ballpark volumes that work for your specific situation.
If you are buying a brew pot, look for one that is taller and narrow rather than a short wide one.

 

[Crafty_Brewer]

If the goal is to do 5 gallon BIAB, I would recommend a 10-15 gallon kettle. I have a 10 gallon and can do up to 1.070 full volume no sparge, and high gravity beers if I feel like sparging a gallon or three. A 15 gallon would have let me do high OG beers full volume without sparging. I also still have to keep an eye on my 10 gallon to prevent boil overs at hot break and when adding hops. I wish my kettle was 15 gallon. My 5 gallon kettle worked great for 1-2 gallon batches.

 

[gmagee]

@McKnuckle 's analogy is a good one.

Recirculating might speed up your conversion a little, and if your mash time wasn't already long enough to get 100% conversion, your conversion efficiency might increase. This will increase your mash efficiency, but not your lauter efficiency.

There are some cases where recirculation can improve lauter efficiency: Mashing configurations that have liquid outside of the grain mass will often have serious sugar concentration gradients between the grain mass wort and the outside wort, with the wort in the grain mass having higher sugar concentration. If you drain the mash without homogenizing the wort throughout it's entire volume, then the wort absorbed by the grain (the wort you don't collect) will have a higher than average sugar concentration, thus lowering lauter efficiency. Recirculation (and stirring also) are effective ways to homogenize the wort, thus leading to somewhat higher lauter efficiency.

In mashing systems with solid sided baskets (aka malt pipes), wort in the vertical space between the basket and vessel wall does not participate in recirculation (unless special steps are taken), thus recirculation (or stirring) does not effectively homogenize the wort, and lauter efficiency suffers.

Brew on

Thanks for this response and also to @McKnuckle. I read the Wiki you linked to and that was also a helpful refresher.