Pros and Cons of BIAB

[jekeane]

One thing I've struggled with in BIAB is cloudy beer. If I use a finer crush, I get cloudier beer. If I don't, I get less efficiency. I've had moderate success with cold crashing/Gelatin fining, but it's an added step.

Anyone got any tips\tricks for clearer beer? It's not like it tastes bad, but some brewing buddies always call it out.

Cloudy beer is a possible result of many things and BIAB in my experience isn't one of them unless possibly you are crushing to absolute flour or your bag material. I use a few different wilser bags and crush my grain relatively fine with some flour but nothing crazy. I get about 84% efficiency with my crush.

Cloudy beer can be caused by: incomplete starch conversion, ph issues, not getting a proper cold break, not using wirfloc or irish moss, particular grains (wheat) to name a few things. I also thing kegging helps clarity arrive much faster than bottling.

I don't take to much care to filter out trub to my fermenter. I havent used gelatin for a good while now unless im very time constrained. I don't cold crash my primary, I just rack to a keg and treat that as my cold crash.

I do use 1/2 tab of wirfloc for 5 gallons. I use a hop spider bag thing. I use an immersion chiller and recirculate ice water to try and be at pitching temps in less than 30 minutes.

All these are biab and were brewed in the last few months.

Raspberry wheat beer less than a week in keg just off 5lbs of fruit.

 

[BlurryEyed]

Wow...84% mash efficiency? Very impressive for any brewer. And yes, you don't have clarity issues, clearly. I use Irish moss, hop spider, cold crashing, and Gelatin to get clarity. My crush isn't flour, but there is some powder. I stir to whirlpool to reduce trub in the primary. I add 2 tsp of gypsum for my water profile.

 

[ArcLight]

What you say is exactly my point. With small grains (i.e. a tight crush) there is more surface area and thus conversion can happen faster.
If you don't want that, because you are mashing hot, you may still get a very fermentable wort. Some recipes call for mashing at 156 or higher, expecting a less fermentable wort. Your beer may be thinner than you hope, since a very tight crush can give faster conversion.

With larger grains, and slower conversion, the Beta Amylase is denatured before it can convert as much starch.

Tiny grains in a 158 degree mash will yield a more fermentable wort than large grains in a 158 degree mash.

I don't think this is correct based on my experience and measurements.

If you increase the surface area and therefore the accessibility of starches and enzymes, it will scale linearly. So if your tight crush increases the conversion rate by 2X, it does so for both enzymes. In other words it comes out the same in half the time.

Example. For a light body beer you might mash at 146 for 90 minutes under a normal crush but if you use a finer crush (assuming you double conversion rate) you will achieve the same results at 45 minutes. You will yield the same amount (and ratio) of fermentable and non-fermentable sugars.

I have observed this first hand when I started crushing using 0.025 in on my mill. For 4 batches I used the normal mash schedule and hit all my gravities. I took gravity readings every 5 min across these batches and determined 30 minutes is sufficient for conversion at a given temp. I hit my FG with light body beer doing this assuming I hit my temp. I do 30 minute mashes now and if you mash at a higher temp you will get the correct ratio of sugar conversion to obtain more body. I will sometimes let a lighter body beer go for 45 minutes just to make sure.

Cheers!

 

[ArcLight]

Yup, it can happen. Smaller particle, with more surface area, can convert faster. Thus Beta Amylase acting on small particles in a hot mash (156+) may have time to convert, while large particles wont be completely converted leaving a less fermentable mash.

Nope. I see no such problems.

 

[urg8rb8]

I use a mash in a bag in a cooler method. Best of all worlds!

 

[Gavin C]

Yup, it can happen.......

Interesting rebuttal.

I'd be very interested to read any information you have to back up your theory.

Like any theory it is only a useful model if real world data can be predicted by it. My brewing experience and my data lead me to believe your theory is bunk.

No difficulty in tailoring a desired FG via among other variables, mash temperature.

From malty stouts and English milds to clean crisp Pilsners, BIAB is not a hurdle to brewing any of these beers.

Maltier Beers with a higher mash temperature.


Drier beers with a lower mash temperature.

 

[applescrap]

Yes, but remember that some of us (me) brew 10 gallon batches indoors. No WAY do I want to deal with bags of hot heavy wet grain.

I think it's really important to recognize that we all have different ideas on what works for us, and multiple bags of wet grain, or a pulley system with one big bag of grain, may not work inside my laundry room.

Good points here. I respect this and never thought of it this way before. Agreed with previous post too, i am a big boy but i still want a pulley, im not getting any younger either. A filter is a filter weather be a bag or a screen. I have come to understand that with brewing a bag you gotta get the bag up and out and there's no cutting the cheese around it. It's gotta be lifted and dealt with. Which led me to believe that using a cooler and draining it might be the best option but then you have to either pump have multiple tiers or have huge arms. I think a huge colander like Gavin uses is the best way to go I pull bag put it in a 8 quart wedding gift pasta strainer over a bucket and squeeze glad to be outside now .

 

[ArcLight]

It's not a theory, it's scientific fact. The tighter the crush, the smaller the grains, and the faster the conversion.
Thus it's possible to have faster and more complete conversion that you realize, resulting in a more fermentable wort than you expected.

You have more control with larger particles , since the starch breakdown is slower, and the mash temperature will have a greater impact because the Beta Amylase will denature before all the starch is fully converted.
The downside is it takes longer.

Your pictures look real pretty, too bad they don't yield any useful information for this discussion.

Interesting rebuttal.

I'd be very interested to read any information you have to back up your theory.

Like any theory it is only a useful model if real world data can be predicted by it. My brewing experience and my data lead me to believe your theory is bunk.

No difficulty in tailoring a desired FG via among other variables, mash temperature.

From malty stouts and English milds to clean crisp Pilsners, BIAB is not a hurdle to brewing any of these beers.

Maltier Beers with a higher mash temperature.
View attachment 352016View attachment 352010

Drier beers with a lower mash temperature.
View attachment 352015View attachment 352017

 

[Gavin C]

It's not a theory, it's scientific fact. The tighter the crush, the smaller the grains, and the faster the conversion.
Thus it's possible to have faster and more complete conversion that you realize, resulting in a more fermentable wort than you expected.

You have more control with larger particles , since the starch breakdown is slower, and the mash temperature will have a greater impact because the Beta Amylase will denature before all the starch is fully converted.
The downside is it takes longer.

Your pictures look real pretty, too bad they don't yield any useful information for this discussion.

As it is a scientific fact I'm sure you will have no difficulty in sharing with us all the empirical evidence in support of this fact. I would have thought you would already have done that by now.

Just to refresh your memory of your stated fact from earlier in the thread; you stated a brewing method utilizing a crush finer than a certain size will prevent a brewer from making a malty beer.

I have no such empirical data to rebut the theory but then it is not my theory so the onus is not on me, it is on you the proponent to make the case.

The pictures were merely to illustrate the weight of anecdotal evidence I have from personal experience. My view based on this experience, to any readers of the thread exploring the use of a bag and fine milling is simply this; there is no greater difficulty making said beers via BIAB.

The only data I have aside form OG/FG is subjective data in the form of medals/ribbons from impartial tasters of these beers ranging from malty to dry.

Again, if you have any or can share a link to any empirical data supporting your theory (not your synopsis of mash kinetics WRT crush size) that malty beers cannot be successfully made via BIAB +finer than standard milling I'm all ears.

If you don't have any data than perhaps you might want to reappraise your position and/or methodology. You do seem mightily attached to it. With appropriate adjustments in technique I'm sure you too can predictably and successfully make malty beers to your liking.

Best of luck.

 

[brew-bandit]

Arclight, I respectfully disagree and second Gavin's comments on evidence.

Finer crush DOES not impact fermentability but TIME does.

We control temperature and pH to adjust the activity of the alpha and beta. This is independent of available starch, or "raw materials." In other words I can optimize enzyme activity even when no starch it present. The enzymes will just sit idle waiting for the raw materials. They will convert as fast as they can based on how accessible the raw materials are.

The time we pick for a mash is based on crush size. Crush size is how accessible the raw materials are to the enzymes. If you have a coarse crush, or in this case "standard", it takes more time for the starches to be accessible. If you use Beersmith and select a light body mash profile it will recommend a 90 minute mash at a low temp. This is to ensure you get max fermentablity. You could mash at 154 degrees f for 2 hours and achieve the same results.

Do a mash with normal crush for 30 minutes at 146 degrees. I bet you will get a full body beer. Do a mash at 154 for 2 hours and I bet you get a light body beer.

A finer crush just means the raw materials are more accessible so the time needed to get the same results is reduced. Remember the enzymes work as fast as they can based on pH and temp independent of amount of starches needing conversion.

If you do a finer crush but don't adjust your mash times then there is some risk you will not get the get the desired results.

I have no problem using a fine crush (.025) and doing a 30 minute mash and achieving a light or full body beer.

Also, there are actual scientific studies on the impact of crush on conversion time. You can google them and you will see the data confirms what I and others are saying.

Either way let's all continue brewing beer and having a great time doing it!

Cheers.

 

[ArcLight]

Finer crush = greater surface area.
A very coarse crush takes longer to gelatinize and for the water to penetrate and for conversion to take place.
A fine crush, allows for faster conversion.

If you have a high temperature with a coarse crush, the Beta Amylase will be denature before it has much chance to work.
With a fine crush, the Beta Amylase is able to do some conversion before it's denatured.

If you mash at a high temperature, because you want a less fermentable beer, the Beta Amylase gets denatured quickly. Lets say by 5 minutes a fair amount is denatured, and by 15 minutes much of it is denatured.
With a coarse crush, thats not enough time for the Beta Amylase to break many bonds, because the water hasn't penetrated the grain.
But with tiny grains, water can quickly penetrate and with a greater surface area, there are more linkages broken, resulting in a more fermentable wort.


Temperature is the key factor in Beta Amylase denaturing, but that denaturing is not instantaneous. It takes 5-10 minutes (for arguments sake). With a very fine BIAB crush you will get more broken linkages than with a traditional mash with coarse grains.

BIAB with a fine crush can give fairly fast conversion, faster than a traditional mash.

Arclight, I respectfully disagree and second Gavin's comments on evidence.

Finer crush DOES not impact fermentability but TIME does.

We control temperature and pH to adjust the activity of the alpha and beta. This is independent of available starch, or "raw materials." In other words I can optimize enzyme activity even when no starch it present. The enzymes will just sit idle waiting for the raw materials. They will convert as fast as they can based on how accessible the raw materials are.

The time we pick for a mash is based on crush size. Crush size is how accessible the raw materials are to the enzymes. If you have a coarse crush, or in this case "standard", it takes more time for the starches to be accessible. If you use Beersmith and select a light body mash profile it will recommend a 90 minute mash at a low temp. This is to ensure you get max fermentablity. You could mash at 154 degrees f for 2 hours and achieve the same results.

Do a mash with normal crush for 30 minutes at 146 degrees. I bet you will get a full body beer. Do a mash at 154 for 2 hours and I bet you get a light body beer.

A finer crush just means the raw materials are more accessible so the time needed to get the same results is reduced. Remember the enzymes work as fast as they can based on pH and temp independent of amount of starches needing conversion.

If you do a finer crush but don't adjust your mash times then there is some risk you will not get the get the desired results.

I have no problem using a fine crush (.025) and doing a 30 minute mash and achieving a light or full body beer.

Also, there are actual scientific studies on the impact of crush on conversion time. You can google them and you will see the data confirms what I and others are saying.

Either way let's all continue brewing beer and having a great time doing it!

Cheers.

 

[brew-bandit]

Finer crush = greater surface area.
A very coarse crush takes longer to gelatinize and for the water to penetrate and for conversion to take place.
A fine crush, allows for faster conversion.

Arclight,

Beta doesn't denature till 160+ degrees. If it denatured as you say then you would have little to no fermentable sugars. Again, temp impacts which enzyme is dominant. Below 160 it can take up to an hour for beta to become completely non active. You can look it up on most brewing site but here is a link to one.

http://braukaiser.com/wiki/index.php?title=The_Theory_of_Mashing

You are correct that a finer crush increases surface area, hence my dicussion in availablilty of raw materials. It the raw materials are 2 times more available then at a given temp and pH the mash time is cut in half to obtain the same results.

Do your own experiments and see for yourself. I have many batches doing this and I hit all my gravities. If you are correct then I am break in the theory of Chemistry.

Cheers