diastatic power recipe considerations

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Arpeggiator

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Ok, i've searched and searched but still can't wrap my head around this. I recently went to my lhbs with a recipe i designed:

10 gal batch

12lbs. maris otter
12lbs. vienna malt
4 lb. cara-pils
2lb. aromatic
2lb. 20L
2lb. rye malt

the guy at the shop told me that the recipe did not have enough DP to allow proper conversion and that my efficiency would be really low. He told me this after he had crushed and bagged the grains. Not wanting everything to go to waste, he told me that if I added 2 lbs of 2 row then I should be in the clear.

I just don't understand the calculation (or why beersmith didn't throw any red flags). If maris and vienna have DP's of 120 and 140, and aromatic and rye clock in at 30 and 105 (briess website), then how am I not in the clear. All the info on the wiki says anything over 35 is self-converting, and i shouldn't be worried about converting the dextrine, right? Was he just blowing smoke, or am i really overlooking something.

What is the formula I should follow when writing a recipe? I've had some efficiency woes since switching to AG but now I feel like that is because the recipes I write are doomed from the get-go (too much specialty grains?). Any advise would be appreciated. Cheers and happy brewing!
 

a10t2

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The rule of thumb is that the total DP, weighted proportionately, should be >35. 50 would be better. MO can be as low as 50, and Vienna can be as low as 100, but even that worst-case scenario puts you over 50 for the entire grist.

If you have more accurate numbers (i.e. you're actually buying all Briess malts), then by all means use those, but the bottom line is you should be fine.
 
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Arpeggiator

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The rule of thumb is that the total DP, weighted proportionately, should be >35. 50 would be better. MO can be as low as 50, and Vienna can be as low as 100, but even that worst-case scenario puts you over 50 for the entire grist.

If you have more accurate numbers (i.e. you're actually buying all Briess malts), then by all means use those, but the bottom line is you should be fine.

I'm sorry, but I still don't know how you add it all up. Do you multiply the weight and DP for each grain then divide by total weight? Why would the guy at the LHBS tell me this if I was already in the clear? Just to sell another $2 of pale? Also, how does one compose a recipe ahead of time not knowing what kind of grains the LHBS carries and their respective DP? Sorry to beat a dead horse...
 

Walker

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You can look up the typical DP of various grains online. (actually, many are on this forum's wiki. It won't be exact from brand to brand or even crop to crop, but it's a good enough for a ballpark.

Looking at your recipe, your LHBS guy either doesn't know what he's talking about, or was trying to just sell you more grain.

1 pound of Marris can convert itself, plus 3 (or so) oz of other grain.
1 pound of Vienna can convert itself, plus 5 (or so) oz of other grain.
CaraPils needs no conversion.
Crystal needs no convertion.
I don't know the numbers on rye, but it can definitely convert itself.

Which leaves you with 2 lbs of aromatic malt that needs someone else to do the conversion for it.

Your base grains can convert themselves plus 6 additional pounds.

You're fine.
 

Walker

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how does one compose a recipe ahead of time not knowing what kind of grains the LHBS carries and their respective DP? Sorry to beat a dead horse...
I would wager that most people don't ever think about it, and don't really need to. I'd bet that most brews are with such a large proportion of grains that have extra conversion power that it really isn't ever an issues when a couple pounds of specialty grains are thrown in.
 

Walker

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Lol. Yup. I thought it was low on DP, but clearly isn't.

So... LHBS guy is either dumb or dishonest then?
 
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Arpeggiator

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Hmmm, thanks guys. A little more searching and I found a blog on the Beersmith website with the formula

"To get this number, just multiply the diastatic power for each grain times the weight of that grain, add the numbers up for all of your grains, and divide by the total grain weight.

Lintner_for_batch = Σ(lintner_for_grain * weight_of_grain) / (total_batch_grain_weight)"

I think the guy at the store was misinformed and not really trying to rip me off.
 

ajf

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I think you may get poor efficiency, not because of inadequate DP, but simply because you have 34 lbs grain for a 10g batch. That is a very large amount of grain for 10g, and efficiency usually drops as the amount of grain increases.

-a.
 

ScottD13

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I did an all munich beer: 10lb lt munich, 4lb dk munich, 1lb caramunich...it converted just fine but I did do a 90 minute mash just to play safe as I had concerns about the low DP and a short 60 minute mash.
 

bcgpete

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I'm wanting to do something similar to this recipe, but a partial mash version:

https://www.homebrewtalk.com/f68/imperial-bastard-stout-126650/

I'm trying to figure out this whole diastatic power thing since this is my first try at formulating my own (sorta) recipe.

My question is, do these grains have any power to convert any sugars or are they just there for the flavoring and color?
 

Walker

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I'm wanting to do something similar to this recipe, but a partial mash version:

https://www.homebrewtalk.com/f68/imperial-bastard-stout-126650/

I'm trying to figure out this whole diastatic power thing since this is my first try at formulating my own (sorta) recipe.

My question is, do these grains have any power to convert any sugars or are they just there for the flavoring and color?
If you are talking about these grains from that recipe thread:
1/4lb black patent
1/2lb crystal
1/4lb chocolate malt
1/2lb roasted barley
Then the answer is: No, those grains do not have diastic power, but they also do not need to have any conversion done on them. They are flavor and color only, so if you are just planning to take out some of the DME from that recipe and put in some 2-row instead, then you are fine.
 

prosper

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I've converted witbiers with 50% unmalted adjunct load before, and dry stouts pretty high in the 'diastatic malts-to-everything-else' ratio as well
 

Jagdmusik

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I've been trying to learn more about diastatic power in order to make room in my recipes for additional specialty grains, and Google brought me to this thread. At this point I'm puzzled: what the heck do you actually need to worry about having surplus DP for converting?

Not base malts, since they already have surplus DP;
Not crystals/caramels, since they're pre-converted;
Not chocolates/blacks, since they've got little that's useful to convert;
Not some specialty malts or malted adjunct grains either, since even they frequently have DP of 30+Lintner...

An illuminating list of grains gleaned from manufacturers' websites: Briess red wheat malt (DP165), Briess 6-row malt (160), Briess white wheat malt (160), Briess rye malt (105), Dingemans Pilsen (90), Briess mild (65), Gambrinus Honey (50), Dingemans Aromatic (30), Briess Munich 10L (30) ...which leaves what, that you'd actually need to worry about?: Unmalted grains, Munichs darker than 10L, Biscuit/Victory/amber/brown malts, probably melanoidin and maybe acidulated (Weyermann doesn't provide DP numbers).

This leads me to the conclusion that many traditional rules of thumb concerning how much base malt you need to compensate for other stuff and get to that overall DP30-50 sweet spot are based on a couple historical issues that don't necessary apply to a modern brewer:
1) the weak diastatic power of British base malts (hard to find hard numbers but I gather you shouldn't expect higher than in the 60's), and
2) the traditional use of unmalted adjuncts, rather than malted ones.

...so if you're using Brit base malt you need at least a pound to convert a pound of amber, and probably two or more to do so comfortably, so it makes sense that such specialties would necessarily be sparingly-used in recipes. If you're using unmalted wheat and German Pils malt (DP110 I hear), you need the traditional 1/3 portion of base malt to convert the wheat. But if you're using modern American malted grains, these guidelines go out the window, don't they? Seems to me that there's nothing stopping you from making 100% wheat or rye beer, no barley at all, since Briess' malted wheat is on par with 6-row's massive diastatic power (just don't skimp on the rice hulls, hehe).

It hardly seems like you'd ever need to worry about diastatic power at all unless you're just going totally OVER THE TOP with something from that quite small list of grains to be concerned about... like a beer that's 75% Victory or something. And in that case, the bigger question in my mind is how your recipe would taste, not whether you can manage to convert everything in the mash.
 

Bobby_M

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DP problems seem to come up mostly with folks who want to try partial mashing and they forget to include base malts since a big pile of specialty malts and adjuncts look innocent enough. You gain quite a bit of yield from caramalts by mashing them by the way. You're right though, there are very few all grain recipes that you'd ever have to worry about.

 
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