BIAB/Full Volume Mash and wort fermentablity

[slcalex]

I just wanted to chime in as well. I've been doing BIAB partial mash usually with about 8lbs grain and 2lbs DME.

I get my grain double milled and mash 150-151 for 60 minutes. I've noticed consistent low FG, 1.008-1.007. I have yet to try higher mash temps.

I am not doing full volume BIAB, and usually sparge with 1.5 gallons. So maybe this lends to the theory of finer crush plus long mash equals greater fermentability??

Edit: Also I use US-05 exclusively and am consistently getting around 85% attenuation. No oxygenation other than a vigorous transfer from kettle to fermenter.

 

[BroStefan]

Just getting caught up reading posts after a few days. Thanks to all who have chimed in.

I hope to brew on Monday and will try the shorter mash time at my "standard" temp. that seems to be the consensus.

I'll keep you all posted.

 

[bobbrews]

The grist/water ratio factor influences the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer.

As always, time changes everything; it is the final factor in the mash. Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting.

A compromise of all factors yields the standard mash conditions for most homebrewers: a mash ratio of about 1.5 quarts of water per pound grain, pH of 5.3, temperature of 150-155 F and a time of about one hour. These conditions yield a wort with a nice maltiness and good fermentability


Tip: If brewing via Partial Mash, and making a dry style like an IPA, then it would be best to mash the grain you have in the mid to upper 140s. The low mash temp. gives you some control and will offset the standard 153-154 F temp. that the extract manufacturer probably mashed at.

 

[RM-MN]

The grist/water ratio factor influences the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer.

As always, time changes everything; it is the final factor in the mash. Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting.

A compromise of all factors yields the standard mash conditions for most homebrewers: a mash ratio of about 1.5 quarts of water per pound grain, pH of 5.3, temperature of 150-155 F and a time of about one hour. These conditions yield a wort with a nice maltiness and good fermentability


Tip: If brewing via Partial Mash, and making a dry style like an IPA, then it would be best to mash the grain you have in the mid to upper 140s. The low mash temp. gives you some control and will offset the standard 153-154 F temp. that the extract manufacturer probably mashed at.

I love the part about the thinner mash slowing the conversion. Using iodine as an indicator (I know, it's flawed) the change from starch to sugar in my fine milled grain and thin mash is complete in about 3 minutes. If the thin mash is slowing conversion, why shouldn't I be mashing thicker and shorter, like maybe 1 minute instead of 1 hour?

I just made a beer using the 1.5 qts/lb and mashed it for 30 minutes at 156F. That should make a very malty beer. Update in about 3 weeks.

 

[doug293cz]

I love the part about the thinner mash slowing the conversion. Using iodine as an indicator (I know, it's flawed) the change from starch to sugar in my fine milled grain and thin mash is complete in about 3 minutes. If the thin mash is slowing conversion, why shouldn't I be mashing thicker and shorter, like maybe 1 minute instead of 1 hour?

I just made a beer using the 1.5 qts/lb and mashed it for 30 minutes at 156F. That should make a very malty beer. Update in about 3 weeks.

Braukaiser has shown that the part about thinner mashes resulting in more fermentable wort is not necessarily true (http://braukaiser.com/wiki/index.ph...ncy_in_single_infusion_mashing#Mash_thickness.) The assertion about conversion being slower in thinner mashes is questionable as well. The author ignores all variables other than enzyme concentration in the analysis, with no consideration for things like increased molecular mobility in more dilute solutions, higher sugar concentration gradients at the particle surfaces (quicker diffusion of soluble species out of the grain), and who knows what else.

Brew on

 

[BroStefan]

I brewed my Brown Porter on Monday. I know this is not the best way but I decided to change two variables. I mashed at 154 (not at 152 as usual) and I closely monitored the SG of the mash and as soon as it hit my target (1.048) I fired it up to 168 F, held for 5 minutes and then pulled the grain. From dough in to grain out was 35 minutes.

FYI - I have a direct fired RIMS system so my temp control is tight.

Pitched WLP 013 London Ale from a 1.5L starter at 3 pm Monday. By 5 am Tuesday there was very active fermentation. By Thursday things had slowed down and I took a SG reading

Beersmith estimated a FG of 1.016. We are now at 1.018. It will loss a few more points I should think.

The mouth feel is just right there and the malt profile is good.

I think I've have it figured out. Shorter times and higher mash temp may have over corrected a little but I'm much closer to where I want this beer to be. I'll fine tone these variables from this point.

Thanks for the comments and insights.

 

[Psylocide]

I brewed my Brown Porter on Monday. I know this is not the best way but I decided to change two variables. I mashed at 154 (not at 152 as usual) and I closely monitored the SG of the mash and as soon as it hit my target (1.048) I fired it up to 168 F, held for 5 minutes and then pulled the grain. From dough in to grain out was 35 minutes.

FYI - I have a direct fired RIMS system so my temp control is tight.

Pitched WLP 013 London Ale from a 1.5L starter at 3 pm Monday. By 5 am Tuesday there was very active fermentation. By Thursday things had slowed down and I took a SG reading

Beersmith estimated a FG of 1.016. We are now at 1.018. It will loss a few more points I should think.

The mouth feel is just right there and the malt profile is good.

I think I've have it figured out. Shorter times and higher mash temp may have over corrected a little but I'm much closer to where I want this beer to be. I'll fine tone these variables from this point.

Thanks for the comments and insights.

Wanted to chime in on this quickly (though late), even mashing for 30 mins, I am getting over 80% attenuation with mash thickness of 1.33 and sparging to volume.

I think the fine crush has to be at least somewhat to "blame." I recently (Sunday) mashed at 3° higher than I thought was needed in my recipe purely to account for the higher attenuation rates I've been experiencing.

Very interested to see how it works out for me... if I can nail down this variable, I'll be well on my way to consistent brews.

 

[BroStefan]

Wanted to chime in on this quickly (though late), even mashing for 30 mins, I am getting over 80% attenuation with mash thickness of 1.33 and sparging to volume.

I think the fine crush has to be at least somewhat to "blame." I recently (Sunday) mashed at 3° higher than I thought was needed in my recipe purely to account for the higher attenuation rates I've been experiencing.

Very interested to see how it works out for me... if I can nail down this variable, I'll be well on my way to consistent brews.

Your results are consistent with mine. Since my last post the Brown Porter is on tap back to what it was when I made it on my 3V batch spurge system.

I also have done a Helles using the same method. I mashed 2 deg F higher and pulled the grain at 45 minutes - as soon as my (full volume) mash hit the target SG. It is fermenting now by the wort seemed to be what I wanted.

 

[JohnSand]

Thank you all for contributing to this thread. My BIAB also over attenuates. I didn't really think much about it, but recently I have had comments like "light" or even "thin". I'm probably brewing today, I will shorten the mash at a higher temp.

 

[Psylocide]

Thank you all for contributing to this thread. My BIAB also over attenuates. I didn't really think much about it, but recently I have had comments like "light" or even "thin". I'm probably brewing today, I will shorten the mash at a higher temp.

Do shorten your mash length if you want to, but I don't think it has much (if anything) to do with this.

I'm pretty comfortable attributing this to the grain crush unless someone can prove me wrong. I'd be interested to learn what someone doing BIAB with a "traditional" crush has to say on the issue.

I would say, mash for however long you want (as long as you get conversion), but mash at a higher temp.

What does your crush look like?

 

[Iseneye]

Do shorten your mash length if you want to, but I don't think it has much (if anything) to do with this.

I'm pretty comfortable attributing this to the grain crush unless someone can prove me wrong. I'd be interested to learn what someone doing BIAB with a "traditional" crush has to say on the issue.

I would say, mash for however long you want (as long as you get conversion), but mash at a higher temp.

What does your crush look like?

I only BIAB but get all my grains with a standard crush from an online supplier. I have never had an over attenuated beer. Standard FG is 1.012-1.013 for majority of brews. Cream ale finished 1.011.

 

[Psylocide]

I only BIAB but get all my grains with a standard crush from an online supplier. I have never had an over attenuated beer. Standard FG is 1.012-1.013 for majority of brews. Cream ale finished 1.011.

I spoke to another member that has shared the same experience.

At least for me, something has to be happening with the fine crush that is causing it, IMO. I am no expert and don't know thing 1 about detailed mash science... but there seems to be a pattern here that my pea-brain can't ignore.

Or I don't have my process fine tuned to the point where multiple variables are still in play.

Tough to say, but we'll see how my increased mash temp affects my current brew and gets me closer to where I think it should end up if I were mashing at a lower temp than is "traditionally" needed for the intended target.

 

[doug293cz]

I spoke to another member that has shared the same experience.

At least for me, something has to be happening with the fine crush that is causing it, IMO. I am no expert and don't know thing 1 about detailed mash science... but there seems to be a pattern here that my pea-brain can't ignore.

Or I don't have my process fine tuned to the point where multiple variables are still in play.

Tough to say, but we'll see how my increased mash temp affects my current brew and gets me closer to where I think it should end up if I were mashing at a lower temp than is "traditionally" needed for the intended target.

Yes, it's your fine crush. Things happen faster in the mash because of it. My explanation here my be of some help in understanding why.

Brew on

 

[TexasWine]

Yes, it's your fine crush. Things happen faster in the mash because of it. My explanation here my be of some help in understanding why.

Brew on

I read your post, but I didn't see anything that directly correlated crush particle size with attenuation. Did I miss it? I did see the connection between speed of conversion and particle size.

 

[doug293cz]

I read your post, but I didn't see anything that directly correlated crush particle size with attenuation. Did I miss it? I did see the connection between speed of conversion and particle size.

With the fine crush, all the diffusion related processes happen faster, due to shorter diffusion distances. So, you get the soluble starch into solution quicker. The smaller particles don't affect the rates of denaturing amylase enzyme, especially the beta amylase. Thus the enzymes have more starch to work on sooner, while their activity is still high (because of less time to denature.) More net action from beta amylase will give you more fermentable wort.

Does this help?

Brew on

 

[JohnSand]

Do shorten your mash length if you want to, but I don't think it has much (if anything) to do with this.

I'm pretty comfortable attributing this to the grain crush unless someone can prove me wrong. I'd be interested to learn what someone doing BIAB with a "traditional" crush has to say on the issue.

I would say, mash for however long you want (as long as you get conversion), but mash at a higher temp.

What does your crush look like?

Pretty fine today. But not always. And I never did traditional AG, so I have no basis for comparison. I do think that the crush affects it, possibly in conjunction with mash length.

 

[Gavin C]

I have no experience with traditional all grain brewing but have not experienced any batches with lower than anticipated final Gravity using BIAB.

My method employs a full volume no Sparge method with 5.5 gallon batches to the FV

My typical brew house efficiency is now 80-82% though I am not sure what relevance that has to the question at hand.

Obviously I have no data with which to compare but I would proffer 1 question. We're mash acidification adjustments being made with the traditional processes. If so, have these measures been tailored to meet the needs of a thinner full volume no Sparge mash?

It is perhaps something to add to the topics of consideration relating to the levels of attenuation on foot of altered maltose: dextrin ratios in the wort.

Perhaps this is entirely irrelevant nonsense on my part. Would love to hear from others more knowledgeable on the subject. I think if this thread were in the brew science section the OP might get better responses than the likes of me blowing smoke.

 

[BowAholic]

Great information here! thanks...
I had been doing AG with my tun but have done a half dozen brews this past month using the method described. I've been very happy with it and even taught a friend to brew this way. My efficiency has been right at 83-85%, which has resulted in higher ABV beers, which is OK for now. I do have a question though, that I know someone here can answer. Since we are brewing with full water volume, and since the grain produces the low pH that we desire, doesn't the additional water volume dilute the mix resulting in a higher pH? I know that my water starts out at around 7, but have been told that it can be as high as 8.5 at times. It would seem logical that the 7.5 gallons of water and my usual 10# of pale ale barley that the pH couldn't get to that 5.1-5.8 area we need...and as I understand it, I actually would be better off at the lower end of that scale since I make lighter colored beers...? I'm probably just over thinking this and missing something, but would like to know. Other than my water/pH question, I couldn't be happier. Thanks OP!
Bob

 

[Gavin C]

Great information here! thanks...
I had been doing AG with my tun but have done a half dozen brews this past month using the method described. I've been very happy with it and even taught a friend to brew this way. My efficiency has been right at 83-85%, which has resulted in higher ABV beers, which is OK for now. I do have a question though, that I know someone here can answer. Since we are brewing with full water volume, and since the grain produces the low pH that we desire, doesn't the additional water volume dilute the mix resulting in a higher pH? I know that my water starts out at around 7, but have been told that it can be as high as 8.5 at times. It would seem logical that the 7.5 gallons of water and my usual 10# of pale ale barley that the pH couldn't get to that 5.1-5.8 area we need...and as I understand it, I actually would be better off at the lower end of that scale since I make lighter colored beers...? I'm probably just over thinking this and missing something, but would like to know. Other than my water/pH question, I couldn't be happier. Thanks OP!
Bob

I think the more dilute mash is likely a factor with pH changes from the grains being tempered by the greater water volume. I have been using calculated mash acidification of late. The calculations just need to acount for the higher water volume to bring the target pH into range.

Some recipes with brewing incorporating a sparge will often mention a thinner mash being used to minimize the acidification in grain bills containing alot of roasted or dark components. So I suppose this is the same process only in reverse.

 

[BroStefan]

Great information here! thanks...
I had been doing AG with my tun but have done a half dozen brews this past month using the method described. I've been very happy with it and even taught a friend to brew this way. My efficiency has been right at 83-85%, which has resulted in higher ABV beers, which is OK for now. I do have a question though, that I know someone here can answer. Since we are brewing with full water volume, and since the grain produces the low pH that we desire, doesn't the additional water volume dilute the mix resulting in a higher pH? I know that my water starts out at around 7, but have been told that it can be as high as 8.5 at times. It would seem logical that the 7.5 gallons of water and my usual 10# of pale ale barley that the pH couldn't get to that 5.1-5.8 area we need...and as I understand it, I actually would be better off at the lower end of that scale since I make lighter colored beers...? I'm probably just over thinking this and missing something, but would like to know. Other than my water/pH question, I couldn't be happier. Thanks OP!
Bob

I don't have enough chemistry to get everything in John Palmer's "Water" but this is what I've figured out from reading and experience

The out-of-the-tap Ph matters but not that much. My tap Ph can very a lot but the buffering capacity of the grist sorts it out.

What matters is the mash Ph. More water does require more acid, but is not linear. Doubling the volume does not double the acid needed. Maybe it is 50% more?

My practice is to add lactic to the water as it heats based on my experience. I'll add 3 ml for a light beer, as an example. My water is a little low in calcium so I'll add 2g CaCO3 and 2g Gypsum for every beer. If I want to adjust the malt/hop balance I'll do that after it is kegged. (got this tip from Gordon Strong's Brewing Better Beer.)

I have a Ph meter now but most of this I figured out with high quality Ph paper.

Of course, YMMV.

 

[BowAholic]

I think the more dilute mash is likely a factor with pH changes from the grains being tempered by the greater water volume. I have been using calculated mash acidification of late. The calculations just need to acount for the higher water volume to bring the target pH into range.

Some recipes with brewing incorporating a sparge will often mention a thinner mash being used to minimize the acidification in grain bills containing alot of roasted or dark components. So I suppose this is the same process only in reverse.

I have never worried about pH as long as I used a normal volume of water for the mash/sparge, so I never bought or used pH test paper or a pH meter, and I'm not familiar with "using calculated mash acidification" unless it's something like Bru'n Water, that I just started trying to understand...those charts have me needing a beer! LOL
thanks,
Bob

 

[BowAholic]

I don't have enough chemistry to get everything in John Palmer's "Water" but this is what I've figured out from reading and experience

The out-of-the-tap Ph matters but not that much. My tap Ph can very a lot but the buffering capacity of the grist sorts it out.

What matters is the mash Ph. More water does require more acid, but is not linear. Doubling the volume does not double the acid needed. Maybe it is 50% more?

My practice is to add lactic to the water as it heats based on my experience. I'll add 3 ml for a light beer, as an example. My water is a little low in calcium so I'll add 2g CaCO3 and 2g Gypsum for every beer. If I want to adjust the malt/hop balance I'll do that after it is kegged. (got this tip from Gordon Strong's Brewing Better Beer.)

I have a Ph meter now but most of this I figured out with high quality Ph paper.

Of course, YMMV.

thanks! I guess I need to get something to test pH, but your additions sound like something that might help...my Calcium is 18 ppm and I brew a blonde or amber about once a week...
Bob

 

[Gavin C]

I have never worried about pH as long as I used a normal volume of water for the mash/sparge, so I never bought or used pH test paper or a pH meter, and I'm not familiar with "using calculated mash acidification" unless it's something like Bru'n Water, that I just started trying to understand...those charts have me needing a beer! LOL
thanks,
Bob

Yes I use Bru'n water

Lactic acid or acidulated malt as indicated. Mash pH (actual measured) with a decent meter and compared with predicted mash PH from software to allow tailoring of the data for future brews.

With lighter grain bills it is more relevant and important with thin mashes.

My pH meter and associated chemicals

Mash pH has a bearing not only on extraction efficiency, but also maltose/dextrin ratios and flavor it would seem. I an of course just parroting others work here. Nothing datawise outside of my own limited experience.

 

[Gavin C]

thanks! I guess I need to get something to test pH, but your additions sound like something that might help...my Calcium is 18 ppm and I brew a blonde or amber about once a week...
Bob

Calcium at those levels is a bit low. Bru'n Water also gives a list of target water profiles that are of use.

 

[BowAholic]

Calcium at those levels is a bit low. Bru'n Water also gives a list of target water profiles that are of use.

I'm trying to understand the Bru'n Water stuff... just need to see what to add and how much... then make a trip to the nearest supply store which is 50+ miles away.
What I have put in so far shows that my most used pale ale/vienna recipe will produce about a 5.6 pH, so I'm close.

 

[Iseneye]

I'm trying to understand the Bru'n Water stuff... just need to see what to add and how much... then make a trip to the nearest supply store which is 50+ miles away.
What I have put in so far shows that my most used pale ale/vienna recipe will produce about a 5.6 pH, so I'm close.

I only do BIAB and I did several years brewing without pH / flavour ions control. Last year I bought the Hach Pro+ meter shown in Gavin's post above. I have now done about 6 brews with pH adjustments.

I have found that using the EZ spreadsheet and Brun water the predicted pH levels are lower than what I am measuring with full volume no sparge BIAB - i.e. spreadsheets with lactic acid and ion adjustments are predicting 5.4 but I'm measuring around 5.6. I picked up the difference on my first brew so have allowed for it on others and have been hitting targets. I believe that the spreadsheets do not calculate full volume mash pH correctly (at least for me).

The reason why I say all of the above is that you may think you're getting 5.6 based on the spreadsheets but it may actually be 5.8. AJ reinforces this but you need to measure your pH with a good meter - don't assume the spreadsheets will be giving you the actual pH.

 

[wobdee]

I've done 4 BIAB full volume batches with my cheap $20 PH meter and so far they have all been within .1 pH of my Brewers Friend calculations. Close enough for me.

 

[Iseneye]

I've done 4 BIAB full volume batches with my cheap $20 PH meter and so far they have all been within .1 pH of my Brewers Friend calculations. Close enough for me.

If it's a cheap meter it's probably only accurate to +/- 0.1 (or worse).

 

[BowAholic]

I only do BIAB and I did several years brewing without pH / flavour ions control. Last year I bought the Hach Pro+ meter shown in Gavin's post above. I have now done about 6 brews with pH adjustments.

I have found that using the EZ spreadsheet and Brun water the predicted pH levels are lower than what I am measuring with full volume no sparge BIAB - i.e. spreadsheets with lactic acid and ion adjustments are predicting 5.4 but I'm measuring around 5.6. I picked up the difference on my first brew so have allowed for it on others and have been hitting targets. I believe that the spreadsheets do not calculate full volume mash pH correctly (at least for me).

The reason why I say all of the above is that you may think you're getting 5.6 based on the spreadsheets but it may actually be 5.8. AJ reinforces this but you need to measure your pH with a good meter - don't assume the spreadsheets will be giving you the actual pH.

that's exactly why I posted the first question...It only makes sense that the pH would be less acid than predicted...so I definitely need top get a pH meter and figure out how to use the water software... dang it!

 

[Iseneye]

that's exactly why I posted the first question...It only makes sense that the pH would be less acid than predicted...so I definitely need top get a pH meter and figure out how to use the water software... dang it!

Be careful because I'm a sample size of one I just read the Brulosophy report on pressure fermentation and noted that he was doing BIAB for the first time. From his page:

First, my target mash pH of 5.7 was way off of my 5.4 calculated pH.

Which corresponds with what I am getting. Around 0.2-0.3 differential.

If you are going to purchase a pH meter read AJ's thread in brewscience sub-forum. Cheap meters are a waste of time and money.