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BIAB - Faster Conversion, Higher Fermentability?

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Bassman2003

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Hello,

I made the switch to full volume mashes a year or two ago after many years batch sparging. Some of my beers are better, some are just ok with a general lack of maltiness and or body.

I am trying to figure out what is different with full volume mashes and how to compensate. You can read references on this site that state both less and more enzymatic activity with BIAB. So I do not know which is correct.

What is your experience and do you think BIAB results in more fermentable wort?

Do you find the need to mash a little higher? if so, how much higher?

Thanks for your input.
 

dmtaylor

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I BIAB, but I maintain a mash ratio of no more than 2 qt/lb and I sparge. I have read in various sources that we should not mash more than 3 qt/lb because doing so dilutes the enzymes too much. You might want to reserve much of your water for the very end of the mash.

There is no reason BIAB should result in more fermentable wort. I have not found this to be the case. If you find your beers are lacking in body, perhaps your efficiency is too high? Or your water too hard? Your mill gap too tight? Mashing too long? I've been mashing for only 40 minutes for the past 10 years with no ill effects because it's a waste of time to mash longer than that for most styles (except maybe Belgians). If you mashed for much longer, like 75-90 minutes, this would certainly hurt body. You could try that and see if you like the results better.

A few things to think about. Good luck.
 
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Bassman2003

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Thanks for your input. Too many things to think about! Your posts brings up the push and pull of the situation though. By doing a sparge with BIAB it is not truly a full volume mash. You then need a separate pot to heat sparge water.

If a sparge is "better" then what about all of the full volume BIAB'ers who swear by the approach?

I do notice my attenuation being better since moving to BIAB. A helles that used to finish around 6.5 brix (non adjusted straight reading on my refractometer) now finishes at 6. That is fine but the beer has less malt character.

On the flip side, my hefeweizens used to be a bit chewy. With the full volume step mashes they are the best they have ever been.
 

dmtaylor

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Thanks for your input. Too many things to think about! Your posts brings up the push and pull of the situation though. By doing a sparge with BIAB it is not truly a full volume mash. You then need a separate pot to heat sparge water.

If a sparge is "better" then what about all of the full volume BIAB'ers who swear by the approach?

I do notice my attenuation being better since moving to BIAB. A helles that used to finish around 6.5 brix (non adjusted straight reading on my refractometer) now finishes at 6. That is fine but the beer has less malt character.

On the flip side, my hefeweizens used to be a bit chewy. With the full volume step mashes they are the best they have ever been.
A sparge is not better. I don't always do it. For low gravity beers below about 1.045, I don't sparge because efficiency is so high even without the sparge. But I don't have to and I would NOT say it is "better" to sparge. In fact I am currently running experiments to see if sparging might even hurt malt flavors. I theorize that it might. So if you're not sparging, and you still have thin watery beer, this continues to perplex me.

Your improvement in attenuation could possibly be from improved conversion due to a finer crush as advocated by BIAB experts. If your crush sucked previously but now is improved, the enzymes can reach more of the starches for more complete conversion. Any efficiency gain from this might be counterbalanced by the lack of sparge if you previously sparged.

How's that for too many variables! I think it might be correct though. If your crush is better now but you're not sparging, could this affect perception of malt flavors significantly? Quite likely, but I must confess I don't really know for sure.
 
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Bassman2003

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I thought a discussion would be nice to maybe get to the bottom of this.

So just ot be clear, you think BIAB should make more malty/body beers? Sparging might take some of these qualities away? Your use of sparging is more for efficiency.

I was leaning towards this premise that BIAB favored the alpha enzymes which result in more body in the finished beer. So my last beer I brewed an APA and set the mash for ~147f for 25 min, 152f for 30 min and 160f for 10 min. I thought this should help will beta but still have enough time in the alpha stage. This beer is just o.k. with a general lack of malt character. So I could just mash at 153f the whole time... I did that with the same beer 6 month ago. The beer had more body but the malt flavor was still kind of muted.

When I batch sparged the malt flavor would just hit you over the head. It was just a huge part of the flavor. I don't think it is just attenuation or mash temps. That is why I am looking for others' experiences.

BTW, my crush has remained the same, just normal, not huge flour.
 

Gavin C

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Hello,

I made the switch to full volume mashes a year or two ago after many years batch sparging. Some of my beers are better, some are just ok with a general lack of maltiness and or body.

I am trying to figure out what is different with full volume mashes and how to compensate. You can read references on this site that state both less and more enzymatic activity with BIAB. So I do not know which is correct.

What is your experience and do you think BIAB results in more fermentable wort?

Do you find the need to mash a little higher? if so, how much higher?

Thanks for your input.
Based on my own data set this is a complete non-issue.

No alterations to recipe/mash profile other than the obvious slightly altered mash pH considerations are needed if doing full volume mashes

There is some good data from the Braukaiser on this very topic of fermentability and mash thickness.

An extract from the page
The results for mash thickness were somewhat surprising. Contrary to common believe no attenuation difference was seen between a thick mash (2.57 l/kg or 1.21 qt/lb) and a thin mash (5 l/kg or 2.37 qt/lb). Home brewing literature suggests that thin mashes lead to more fermentable worts, but technical brewing literature suggests that the mash concentration doesn't have much effect in well modified malts [Narziss, 2005].
 
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Bassman2003

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Thanks for your input Gavin. So data shows an actual nod to BIAB for extraction and efficiency.

Do your BIAB beers have plenty of malt flavor/body? Have you ever brewed non-BIAB to compare to?

I am just wondering beyond efficiency and extraction if there could still be a flavor difference?
 

Gavin C

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Thanks for your input Gavin. So data shows an actual nod to BIAB for extraction and efficiency.

Do your BIAB beers have plenty of malt flavor/body? Have you ever brewed non-BIAB to compare to?

I am just wondering beyond efficiency and extraction if there could still be a flavor difference?
No worries mate.

Some of my more malty beers have fared well in competitions and have scored well. Body/mouthfeel/malty/dry is governed by the same mash parameters as with any n-vessel setup. Mash thickness in and of itself is not a variable that concerns me.

All my beers are made using a bag as a manifold and thin mashes.

It appears to me to be a complete non-issue.

I have not brewed with a conventional mash-tun or water:grist ratio

Malty, dry, hoppy, bitter, etc. The brewing world is your oyster if you choose to utilize a no-sparge approach.

FWIW, I brewed a malty style this morning. A Marzen.
 

wilserbrewer

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You then need a separate pot to heat sparge water.

.

I believe the Kaiser researched this and found a cold sparge works equally as well, with the only downside being an increased time to reach boil.

Another approach I have used, mainly to save heating time while making large batches, is to mash in with around 60% of the total water, then after 40 minutes or so add the remaining water to the mash at say 160 - 180 degrees, stir well, wait a few minutes, stir well again and remove the bag .

This technique gets my grain mashing 20 minutes sooner than heating the full volume.
 
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Bassman2003

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Thanks for your input Gavin. So from your perspective, BIAB should be no different.

How about water treatment? I read somewhere that full volume sized mashes might lend themselves better to water treatment. I put all of my water treatments (calcium chloride, lactic acid etc...) in right at the start and let them recirculate while the water comes up to temperature. This gives the treatment about 10-20 minutes of time before the grain is added. I used to heat up the mash water in my HLT. When the temperature was correct I put it in the mash tun. I then would add my water treatment and the grain would soon follow.

Maybe there is a pH difference between the two methods? My pH meter crapped out so I am just going by software at this stage. Plenty of foam present during the mash but maybe I am going too far with the pH?
 
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Bassman2003

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I believe the Kaiser researched this and found a cold sparge works equally as well, with the only downside being an increased time to reach boil.

Another approach I have used, mainly to save heating time while making large batches, is to mash in with around 60% of the total water, then after 40 minutes or so add the remaining water to the mash at say 160 - 180 degrees, stir well, wait a few minutes, stir well again and remove the bag .

This technique gets my grain mashing 20 minutes sooner than heating the full volume.
Thanks. Yes, a cold sparge was on my mind.
 

Gavin C

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Thanks for your input Gavin. So from your perspective, BIAB should be no different.

How about water treatment? I read somewhere that full volume sized mashes might lend themselves better to water treatment. I put all of my water treatments (calcium chloride, lactic acid etc...) in right at the start and let them recirculate while the water comes up to temperature. This gives the treatment about 10-20 minutes of time before the grain is added. I used to heat up the mash water in my HLT. When the temperature was correct I put it in the mash tun. I then would add my water treatment and the grain would soon follow.

Maybe there is a pH difference between the two methods? My pH meter crapped out so I am just going by software at this stage. Plenty of foam present during the mash but maybe I am going too far with the pH?
Water additions made at the outset. The salts dissolve. Do this before you mash.

Thinner mashes are more dilute meaning all other parameters being equal they will have a higher pH than a thicker mash.

Plan for this by making appropriate pre-emptive (never intra-mash) adjustments to the acid content of the mash.

The same applies regardless of the type of brewing you are undertaking. Thinner mashes simply require more H+ ions to bring the pH into the target range (all else being equal).

Conversely, an often overlooked method to increase a mash pH is to mash thinner. (not an option with full-volume mashing but simple and effective if a sparge-volume is planned)

In short. Two steps.

  1. Salts are the seasoning for the beer. Choose what you want.
  2. pH is adjusted by mash thickness and/or H+/OH- additions.
 

Magnus314

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I get more attenuation/lower FG's with a fine BIAB crush and full volume mash.

Cutting back on the mash time a little was an easy fix.

But to be honest i like drier beer, so it works out ok to let them mash the full 60+ minutes.
 

dmtaylor

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So just ot be clear, you think BIAB should make more malty/body beers? Sparging might take some of these qualities away? Your use of sparging is more for efficiency.
No. I am saying that efficiency and perception of malty flavors are very likely linked. It is for this reason that a no-sparge beer (with an efficiency of say 50-55%) will tend to taste more malty than the same recipe with a grist aimed for a high efficiency, say 85%.

If you used to sparge and with that method got an average efficiency of say 78%, but now you BIAB and no longer sparge and noticed that your efficiency has fallen to say 73%, this loss of ~5% efficiency might possibly be detectable as a gain in malty flavor, because if you knew that with the new process you would get less efficiency, you might/would/should have used a little extra malt in the grist to compensate. In my theory, which I am currently testing, more mass of grains for the same OG recipe will result in more grainy malty flavors in the finished beer. I believe John Palmer would agree with this, at least he would based on his origination of the no-sparge concept ~10 years ago when I began playing with it.

With my current experiment, I am comparing the same recipe, same malt percentages in each batch, but the first batch is no-sparge and the second batch is batch sparged. First batch I got OG=1.052 and 64% efficiency if memory serves, and second batch got OG=1.049 and 81% efficiency (all in "brewhouse efficiency" terms). So, the OGs are comparable but the first recipe used almost 50% more mass of grains than the second batch. The beers taste different already but I am waiting longer to release results as they both have a bit of diacetyl at the moment unfortunately, which could lead to muddled and confusing results. I'm crossing fingers that it fades in a few weeks.
 
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Bassman2003

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DM, cool. I can agree with your direction. So by getting very good attenuation, a malty beer effect might be lessened. I would like to hear about your results.

Gavin, Bru'n water had me in the mash pH range of 5.3 for the current APA that is kind of thin-ish. I have all of my liquid in the mash input and none in the sparge amount input. So I think the theory was correct. I wonder if my previous setup did not give enough time for the pH correction therefore resulting in a little higher pH than I am getting now.? I think my current setup is "brewing right" as I use a Hosehead to control the temps and the beers seem very complete. Just some are not as malty as I want.

So what is my next step to bring some more maltiness in the picture?
 

dmtaylor

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Personally I wouldn't call it "good". There's no way they should be able to get almost identical efficiency and OG with no-sparge vs. sparge -- this calls the whole thing into question. My experiments will be more valid with a far more realistic efficiency swing of >15% but consistent OG.
You're seeing a 15+% efficiency difference when you sparge vs no-sparge?
 

TheBrewBag

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Bear in mind that BIAB is simply employing the use of a filter, which allows a finer grind to optimize the grain potential. The following ExBeeriment from Brulosopher points to a more fermentable wort. http://brulosophy.com/2015/11/23/mind-the-gap-course-vs-fine-crush-exbeeriment-results/

Water to grain ratio is not mentioned here so we're not able to get the absolute facts on whether he mashed low or high, but the increased efficiency and lower attenuation indicate that the finer grist was more accessible to the enzymes. Along with another BIAB'er we've tracked 76 batches at 2.6 WTGR or higher and have averaged 78.4% eff with acceptable attenuation every time. I just recently brewed using 5 lbs of wheat flour which resulted in 88.5% eff. Beersmith screengrab attached.

View attachment Wheat 88.5.pdf
 

doug293cz

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Personally I wouldn't call it "good". There's no way they should be able to get almost identical efficiency and OG with no-sparge vs. sparge -- this calls the whole thing into question. My experiments will be more valid with a far more realistic efficiency swing of >15% but consistent OG.
You're seeing a 15+% efficiency difference when you sparge vs no-sparge?
I wouldn't consider a 15% efficiency difference between sparge (single batch) vs. no sparge "realistic." The results of my lautering simulations are shown below, and my calculations are in agreement with Kai Troester's (http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis.) For 0.12 gal/lb grain absorption (typical for MLT and no squeezing), the average lauter efficiency difference is 8.25%, with an minimum of 6.95% and a max of 9.0%. A double batch sparge will increase the efficiency difference by about 3%. In order to get a larger difference in mash efficiency, the conversion efficiency (mash efficiency equals conversion efficiency times lauter efficiency) needs to be lower for the no sparge case.

No Sparge vs Sparge big beers ratio.jpg

A lower conversion efficiency indicates that saccharification has not progressed to the same degree as for higher conversion efficiency. Less saccharification also likely leads to a larger percentage of unfermentable sugars in the wort, which would likely lead to a maltier flavor. But this has nothing to do with how you lauter (sparge vs. no sparge), but rather how "complete" your mash process is.

Brew on :mug:
 
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Bassman2003

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Thanks for your replies. So it seems BIAB or full volume mashes tend to be very efficient. Solid attenuation is great.

How about flavor/maltiness? Have you guys noticed any trend of BIAB to produce normal, thin, thick beers?
 

dmtaylor

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You're seeing a 15+% efficiency difference when you sparge vs no-sparge?
Yes, but I should clarify: I also did NOT squeeze the bag for the no-sparge batch, so that I might reduce efficiency on purpose. My experiment has more to do with lauter efficiency than anything else, i.e., first runnings or the "extra virgin" runnings will tend to taste better than after a lot of rinsing and pressing, in much the same way as different grades of olive oil are made.
 

dmtaylor

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In order to get a larger difference in mash efficiency, the conversion efficiency (mash efficiency equals conversion efficiency times lauter efficiency) needs to be lower for the no sparge case.

A lower conversion efficiency indicates that saccharification has not progressed to the same degree as for higher conversion efficiency. Less saccharification also likely leads to a larger percentage of unfermentable sugars in the wort, which would likely lead to a maltier flavor. But this has nothing to do with how you lauter (sparge vs. no sparge), but rather how "complete" your mash process is.
Interesting.... I think you've opened my eyes to something. The act of sparging takes time. Not a lot of time necessarily, but perhaps enough for more complete conversion. By not sparging and going straight to a boil as soon as runoff is complete or the BIAB bag is pulled, I could be cutting short the conversion. Hmm...

Compounding my problem(?) and possibly explaining my personal experience of ~15% efficiency difference between sparge and no-sparge, I should point out that I have also been mashing for only about 40-45 minutes on almost every batch for the past 10 years (nearly 100 batches), which is way less mash time than pretty much any other homebrewer. This decision was based on early assessments that brewhouse efficiency doesn't improve significantly by waiting those extra 20-50 minutes, at least not when sparged.

I need to think on this more in the future and ensure further experiments take this difference in mash time into account, and/or mash for at least 75 minutes or something like that to maximize conversion and minimize the impact of skipping the sparge vs. not. Thanks!
 

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Either way time will increase conversion - but after 60 minutes the increase is negligible. The 2 variables most don't employ together when using a fabric filter is grinding at .020 and a WTGR of 2.6 or greater. This creates the optimum conditions for a more complete conversion in less time.
 

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