What BIAB brewing actually is (Mythbusting for traditionalists)

[AdjunctBrewer]

So, per @mabrungard , batch sparging SG typically stays above the 4 - 5 Plato/Brix limit he suggests for minimizing tannin and silicate extraction.

However, if doing multiple batch sparges, the final runnings SG could end up below the 4 Plato/Brix limit, if the pre-boil SG is at the lower end for beer wort.

The grind to dust (grind till your scared, etc...) practice in BIAB might also play a role in tannin extraction especially if the husks are ground to a powder (corona type mill, roller mill w/ too small of a gap) as opposed to left whole (roller mill with correct gap).

There doesn't seem to be any formal studies on BIAB tannin extraction vs grind, SG, pH and temperature - and how one variable affects the others - most just go by pH and temperature constraints. (As opposed to the informal "I always grind till I'm scared and haven't noticed anything...")

 

[doug293cz]

The grind to dust (grind till your scared, etc...) practice in BIAB might also play a role in tannin extraction especially if the husks are ground to a powder (corona type mill, roller mill w/ too small of a gap) as opposed to left whole (roller mill with correct gap).

There doesn't seem to be any formal studies on BIAB tannin extraction vs grind, SG, pH and temperature - and how one variable affects the others - most just go by pH and temperature constraints. (As opposed to the informal "I always grind till I'm scared and haven't noticed anything...")

Something to consider with husks, is that they are thin membranes, and as such, there are very short diffusion distances for water to penetrate and compounds to leach out - if they are going to. Also, because husks are thin, the surface area does not increase much if they are shredded. I doubt husk shredding plays a determinative role in tannin extraction, and that temp, pH, and osmotic pressure play much larger roles.

Brew on

 

[Bobby_M]

I have been using BIAB for several years. This thread is perhaps one of the most useful I have seen for BIAB on this forum. I am no expert but there is a lot of useful discussion in this thread for BIAB. As for myself I do a dunk sparge after mashing, if only to get back to full boil volume. I also use a water temp between 170-180 F to mash out. Maybe it doesn't add much sugar to the wort, but my main interest is getting the full boil volume for the boil as I lose on average 1 gallon from grain mashing in BIAB.

The follow up question is whether you could increase the starting water by 1 gallon to make up for the absorption in advance? That's what most full volume mashers do; anticipate all the losses and built that in to the water calculation. The reason for NOT doing that is that your kettle is too small to accommodate that extra gallon up front, once the grain is added.

 

[AdjunctBrewer]

Something to consider with husks, is that they are thin membranes, and as such, there are very short diffusion distances for water to penetrate and compounds to leach out - if they are going to. Also, because husks are thin, the surface area does not increase much if they are shredded. I doubt husk shredding plays a determinative role in tannin extraction, and that temp, pH, and osmotic pressure play much larger roles.

Brew on

Something to think about:

https://www.homebrewtalk.com/thread...y-astringency-discussion.598719/#post-7836463

For what it's worth, the textbooks used by the German brewing universities like Narziss and Kunze all caution against shredding the husk because it releases a larger quantity of undesirable enzymes like LOX and PPO which can then work to create increased quantities of staling compounds, which can also be astringent. They go through significant lengths to keep the husk intact via processes like steam conditioning, and sometimes even strip away the worst offending parts of the husk like where the arcospire attaches because they contain the greatest concentration of the bad enzymes. But most American craft breweries and homebrewers pay little to no attention to any of that.

 

[North_of_60]

The thread that never dies. Good write up.

I BIAB for 4 reasons:
1. Its all grain
2. It makes great beer
3. The initial cost is minimal
4. I'm lazy, but not lazy enough for extract

I keg for 1 reason:
1. I'm lazy

I ferment in the keg for 2 reasons
1. Cost, I already have the kegs
2. I'm lazy

So bottom line, I'm cheep and lazy.

 

[doug293cz]

Something to think about:

https://www.homebrewtalk.com/thread...y-astringency-discussion.598719/#post-7836463

This is an "appeal to authority" argument, which is one of the common logical fallacies. Do any of those textbooks present real data that compares intact husks to shredded husks to powdered husks w.r.t. to undesirable enzyme concentrations, or tannin, silicate, etc. concentrations, or references to such data? I would be interested in the research that supports the German practices. I prefer to be data driven, not just opinion driven.

With that said, I do not have any measurement data that supports my argument. My argument is based on well established diffusion science, and assumes that diffusion rates are not a function of direction in the husk material, which could be a false assumption (but seems reasonable, at least until contravening evidence is available.)

Brew on

 

[InspectorJon]

They go through significant lengths to keep the husk intact via processes like steam conditioning, and sometimes even strip away the worst offending parts of the husk like where the arcospire attaches because they contain the greatest concentration of the bad enzymes

How would any home brewer ever do that? I can’t prove it but I feel like there must be a lot of other more significant processes we could work on improving before going down the manipulation of barley husks rabbit hole.

 

[AdjunctBrewer]

How would any home brewer ever do that? I can’t prove it but I feel like there must be a lot of other more significant processes we could work on improving before going down the manipulation of barley husks rabbit hole.

That quote isn't from me, it's from a LODO guy named Techbrau in the linked thread.

Dehusking barley at the commercial level is a fairly common operation.

For the homebrewer it would probably suffice to condition the grain before milling.

Do any of those textbooks present real data that compares intact husks to shredded husks to powdered husks w.r.t. to undesirable enzyme concentrations, or tannin, silicate, etc. concentrations, or references to such data?

That's my question also as I don't own those texts.

With that said, I do not have any measurement data that supports my argument.

Well sure, that's why I've asked for any studies done on the subject in #401.

 

[Barão]

Can I make BIAB in the Brewzilla automatic pan ? Would the grain bag be inside or outside the malt basket?

 

[JohnDBrewer]

There's a local brewery where I live and they use a mash press. The grain is completely pulverized, finer then flour by the looks of it. When the mash is complete they run it through the filter. They make good beer and are a big player in the local market. The brewery says their efficiency is in the high 90%. Not sure if they strip the hulls before the grind it to dust. Next time our club has a meeting there I'll get more info. I had never or heard of anything like it so really didn't know what questions to ask. Here's the link to the system.

https://www.brewmation.com/brewing/mash-press

 

[Closet Fermenter]

Can I make BIAB in the Brewzilla automatic pan ? Would the grain bag be inside or outside the malt basket?

I have not done a full biab. I have done a couple full volume mash runs in a Digiboil. This is a 1st generation, 110v unit I got cheap on clearance. I used it, as designed, to heat water. Then, I bought the mash upgrade kit, (again, on clearance), that included a false bottom, malt pipe, and ring to sit the malt pipe on while draining.
The first batch, I just put the grains into the malt pipe. I only had a very small amount of grain escape the pipe and get through the false bottom, but I was a little concerned about scorching.
The next batch, it occurred to me to use my bag inside the malt pipe. I should mention that I am using a corona mill, so I do get some portion of really fine grist in my mash. Wow! Talk about clear, clean wort coming out! I still hit my target OG, so I plan to continue to do this whenever I have a small enough grain bill to fit my unit.
I have done a fly sparge when I didn’t have quite enough room for a full volume mash.
I would think that if you put it outside the malt pipe, it would be about the same thing, but maybe a little awkward to deal with. I would be careful to avoid letting it contact the bottom where it could melt. A false bottom should prevent that.

 

[Closet Fermenter]

Can I make BIAB in the Brewzilla automatic pan ? Would the grain bag be inside or outside the malt basket?

I suppose the real question is should we use the malt pipe at all? There’s a lot of water that surrounds the malt pipe, and on my early model, there’s no pump for recirculating. I can do it manually with a small pot, (I have actually done this), or could hook up an external pump. I could get more grain in there if I ditch the malt pipe. The advantage of the pipe is that it rests on top and drains. I guess the bag sitting on the false bottom is about the same thing.

 

[Halfakneecap]

Can I make BIAB in the Brewzilla automatic pan ? Would the grain bag be inside or outside the malt basket?

Yes, take the malt basket out, but leave the false bottom in. I used to do that in my Robobrew for double batches

 

[Halfakneecap]

I suppose the real question is should we use the malt pipe at all? There’s a lot of water that surrounds the malt pipe, and on my early model, there’s no pump for recirculating. I can do it manually with a small pot, (I have actually done this), or could hook up an external pump. I could get more grain in there if I ditch the malt pipe. The advantage of the pipe is that it rests on top and drains. I guess the bag sitting on the false bottom is about the same thing.

Yes, or you can use clamps to hold the bag up off the bottom, but i found the false bottom is fine. Id stir it a few times through the mash, and id still recirc.

I ended up getting the extension kit for the 35L robo, and now do doubles using the pipe. But before i did that i could get a double batch by using the bag. It was a tight squeeze, and could only work with lower gravity beers ( 1.038 or less ) unless i added sugar to the boil, but it was possible.


I take the central overflow pipe out on my robo, and use a SS bolt to fill the hole. I never fill to that point and it gets in the way for me.