What's the deal with grains and "Max in batch" numbers?

I can get the idea with certain crystal malts and such - don't want to overdo it or the sweetness would be too much etc. But why does White Wheat have a Max in Batch of 60% in Beersmith (Northernbrewer says 50%) and Weyermann Pale wheat has up to 80%? I see White Wheat is listed as having higher diastatic potential so I see it's not a need for base malts to help conversion.

So what is the full deal with those numbers? Why would I not want to do a hefe with 65% white wheat malt? Or are these numbers not really all that much to be concerned about?


Rev.

maybe it's one of those vestigial thoughts from when malts weren't as modified and wheat malt couldn't convert itself. plenty of people have done 100% wheat batches BIAB. however traditional all grain brewers are weary of 100% wheat mashes because it could cause a stuck sparge.

Yeah I've seen people do 100% wheats before and know they are possible as wheat has enough diastatic potential to convert itself - but that just makes the max in batch thing all the more confusing. I just can't get how one wheat is listed as up to 80% and another is listed at 50-60% depending on the source. Just would love to know what that is all about


Rev.

I think it has more to do with sparging than diastase.

GilaMinumBeer said:

I think it has more to do with sparging than diastase.

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If that were the case why would Special B only have a 10% max in batch or 20% for C60?


Rev.

No one??


Rev.

Tinga said:

maybe it's one of those vestigial thoughts from when malts weren't as modified and wheat malt couldn't convert itself.

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Despite this thought, I believe it still has to do with the Diastic power of the malt and its ability to convert.
American Homebrewers Association

Some wheat malts may be able to convert, but probably not as efficiently as they could. Because of how roasted Special B is, it can't convert itself. Hence the 10%. I'm not 100% sure how that translates to BIAB or steeping this in an extract though.

Maybe the % to use is more for an AG brewer to note, but it does have to do with its ability to convert starches to sugars.

luke2080 said:

Maybe the % to use is more for an AG brewer to note, but it does have to do with its ability to convert starches to sugars.

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But if that were the case then why couldn't 20% Special B be used if you were using 80% 2-row with it? That would certainly allow more than enough diastatic power. I'm thinking it's a recommended balance kind of thing, like "Don't add more than xxx or else...." but that still wouldn't explain the wheat thing. With oats I can get it, they have higher oil and fat content and such, so I've read in "Designing Great Beers", but with some other malts I don't exactly get it.


Rev.

luke2080 said:

Despite this thought, I believe it still has to do with the Diastic power of the malt and its ability to convert.
American Homebrewers Association

Some wheat malts may be able to convert, but probably not as efficiently as they could. ....

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No way. Wheat malt has an incredible amount of DP. Much more than pils and maris otter.

I think it's just a general guideline for people new to recipe formulation more than anything else and in no way is it law.

Rev2010 said:

If that were the case why would Special B only have a 10% max in batch or 20% for C60?


Rev.

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Because I think the author is using the percentages in different context per grain type.

Because the guy wanted someone to make a thread to discuss the % usage and to make us use our brains!

Maybe he is trying to tell us something! Like when Mel Gibson was reading the magazines and trying to tell everyone it was a government conspiracy! I bet any money it is something like that....