Crystal Malt acidity is not similar to Caramel Malt acidity

[Silver_Is_Money]

By using a 3 coefficient quadratic regression of DI_pH data which Briess provided to me upon request I have achieved an R squared confidence factor of nearly 94% for the correlation of Lovibond color to DI_pH across their entire range of caramel malts spanning from 10L to 120L. This proves to me that a commonly seen alternative approach of attempting to group caramel malts into "color groups" and thereby assign "group" related acidity values (as opposed to calculating their acidity directly from L color) is a flawed approach that will not achieve such a level as 94% precision, and going with a calculation of DI_pH via L color is indeed the proper means to apply here.

But the same source also contains DI_pH vs. Lovibond color data for a number of crystal malts (presumably from the testing of competitors "crystal process" malts), and my attempts at linear and various methods of non-linear regression of this crystal malt data have at best achieved R squared correlation of about 56% for crystal. The odd data is such that acidity is high (DI_pH is low) for lower L crystal malts, then acidity goes way down (DI_pH's go noticeably up) across the mid-range of L colors, and then acidity dramatically rises again for the highest L range of crystal malts.

My preliminary conclusion from this is that caramel and crystal malts should not be lumped together into a single category for the assignment of acidity via color (as has been commonly done for many years), and the two processes (caramel and crystal, albeit related) likely need to be handled separately and divided into two distinct malt categories. This is somewhat similar to my acidity related conclusion reached for malted and unmalted deep roasted grains, but whereby the solution to deep roasted acidity was rather easy via categorically separating them, the solution for crystal malts may require grouping or some other method (higher order quadratic regression perhaps). Stay tuned.

 

[ScrewyBrewer]

@Silver_Is_Money to me it makes sense that Crystal malts don't change DIpH value in lock step with their color. So using the same formula to calculate the DIpH values for this group of malt ranging in color from (10L/25EBC) to (120L/319EBC) doesn't make sense. It's a good theory if I understand you correctly.

 

[Silver_Is_Money]

Here's one example of just how odd this data is. Crystal malts in the 40-50L color range have lower DI-pH values (and presumably or rather potentially via correlation, higher acidity) than 120L Caramel.

 

[Big Monk]

Here's one example of just how odd this data is. Crystal malts in the 40-50L color range have lower DI-pH values (and presumably or rather potentially via correlation, higher acidity) than 120L Caramel.

But DI pH isn’t the whole story.

 

[Silver_Is_Money]

@Silver_Is_Money to me it makes sense that Crystal malts don't change DIpH value in lock step with their color. So using the same formula to calculate the DIpH values for this group of malt ranging in color from (10L/25EBC) to (120L/319EBC) doesn't make sense. It's a good theory if I understand you correctly.

Yes, but the odd thing is that Caramel malts do highly correlate to color. Perhaps this is simply a matter of a single maltsters Caramel process product exhibiting very good correlation to color vs. what is likely a random grab bag of other maltsters Crystal process product not exhibiting such color correlation?

 

[Silver_Is_Money]

But DI pH isn’t the whole story.

I agree! But quantified titration data is hard to come by sans perhaps for Weyermann malts when purchased by the 25 Kg bag. How many of us are willing to go 100% with their product and buy all of it in 25 Kg bags?

 

[Big Monk]

I agree! But quantified titration data is hard to come by sans perhaps for Weyermann malts when purchased by the 25 Kg bag. How many of us are willing to go 100% with their product and buy all of it in 25 Kg bags?

Well not even Weyermann provides titration data. They are all I use regardless but they don’t provide titration data, just DI pH.

 

[ScrewyBrewer]

The way I and most likely every other homebrewer brews is to pick a beer style and brew it. Last year I brewed Witbier, NEIPA, Porter, Stout, Amber and Brown Ales. Never knowing what I'll want to brew next is the reason I never buy ingredients in bulk.

With such a varied assortment of grain bills and different fermentable types, it makes titration testing impossible for each grain used in every recipe. The one thing I have in my favor is most of the grains I use are Avangard or Briess who as far as I know don't provide DIpH values for their grain batches.

 

[Silver_Is_Money]

With such a varied assortment of grain bills and different fermentable types, it makes titration testing impossible for each grain used in every recipe.

This is why some of us default to the use of inferred or implied titration values, and why I use primarily class combined with color inferred DI_pH values combined with base 10 logarithms as my means to quasi-empirically substitute for titration values. Either way it's always going to be somewhat hit or miss.

 

[Big Monk]

This is why some of us default to the use inferred or implied titration values, and why I use DI_pH combined with base 10 logarithms as a means to quasi-empirically substitute for titration values. Either way it's always going to be somewhat hit or miss.

To be fair, the values I use for DI pH come from the large data pool I have and from the Weyermann. We have something like 101 measured malts of all varieties, with crystal/cara and roasted malts represented in a big way.

 

[mabrungard]

I don't doubt for a moment that the acidity of crystal malts don't follow color very well. However, I know that there are very few brewers that EVER use much dark crystal since it is a very 'flavorful' substance. The resultant effect of not predicting dark crystal malt acidity very accurately, is pretty minor.

Its great that Larry continues to add a data point to the cloud of data that's out there. As Derek points out, DI pH isn't everything.

 

[dmr]

To be fair, the values I use for DI pH come from the large data pool I have and from the Weyermann. We have something like 101 measured malts of all varieties, with crystal/cara and roasted malts represented in a big way.

Are you willing to share these DI pH values?

 

[Big Monk]

Are you willing to share these DI pH values?

Absolutely. PM me with contact info and I’ll break that page out of my malt sheet for you tomorrow.

 

[ajdelange]

The resultant effect of not predicting dark crystal malt acidity very accurately, is pretty minor.

I don't think you understand that what these guys are trying to do is improve mash pH prediction software by accounting for effects that the Gen I programs approximate, ignore or model incorrectly.

As Derek points out, DI pH isn't everything.

Indeed. The three buffering parameters (or at least one of them) are equally important.