A recent thread draw my attention on the fact that under-modified malt, or malt with the lower value of Kolbach Index is less than 35, is extremely difficult if not impossible to find.
In fact, I went around in various sites, including Czech malters, and found no base malt, for which the Kolbach Index was given, that was under 35, i.e. "under-modified" according to the current wisdom. The only way one can get under-modified malt these days appears to be DIY malting or maybe get a "custom" batch from an established malter. Maybe malters have some under-modified malts "under the table" that they keep for clients who specifically ask for that, but in general this is not something that the industry overall seems to demand.
Then I begun asking what really the Kolbach index is, and that is the ratio of total soluble proteins in the wort to total proteins in the malt, after a "Congress mash".
This raises a first order of doubts: how is Congress mash representative of a real-life mash, and up to which extent this number has a meaning for homebrewers.
But then again, this line of reasoning is negated by the fact that, in general, all malts produced are meant by the producers to be easily mashable. Whatever the way that we adopt to measure the degree of modification, what we get is that malsters produce, invariably, a malt which is easy to mash and requires no protein rest no matter what.
The problem is now to understand why there are so many recipes around which still call for a protein rest, and some brewers appear to do that in their practice. Is this just a fossile remnant of past practices, "I do as my grand-grand-mother did because I trust her recipe", paying homage to a tradition for the sake of it, or is still there, in 2021, some real sense and consequence in making a protein rest?
Which is to say: If we forget the definitions of "well-modified" malt and "under-modified malt", and get to the cathegories of "normally modified malt" and "less-than-normally modified malts", where "less than normally" means a Kolbach index of 35 or maybe 36 at the left margin of the fork, does it make any difference, for a less-than-normally modified malt, to make a protein rest? Is there any paper or test which attempted at make two beers identical in every respect except for the protein rest, and then examine the differences in taste, clarity, head retention, shelf durability etc?
Another doubt arises from reading this: The Oxford Companion to Beer Definition of Kolbach index
The reality is that the index is nothing more than a gauge of the extent to which proteolysis has occurred during malting. [...] It reveals nothing about the nature of the solubilized proteins and whether they are or are not problematic or beneficial.
Which can be read as "not all solubilized proteins are created equal and some are problematic" and, maybe, the protein rest is used by some brewers in order to solve those "problems" that would not appear by the simple reading of the Kolbach index.
I am very grateful for either answers or links to interesting sources.
In fact, I went around in various sites, including Czech malters, and found no base malt, for which the Kolbach Index was given, that was under 35, i.e. "under-modified" according to the current wisdom. The only way one can get under-modified malt these days appears to be DIY malting or maybe get a "custom" batch from an established malter. Maybe malters have some under-modified malts "under the table" that they keep for clients who specifically ask for that, but in general this is not something that the industry overall seems to demand.
Then I begun asking what really the Kolbach index is, and that is the ratio of total soluble proteins in the wort to total proteins in the malt, after a "Congress mash".
This raises a first order of doubts: how is Congress mash representative of a real-life mash, and up to which extent this number has a meaning for homebrewers.
But then again, this line of reasoning is negated by the fact that, in general, all malts produced are meant by the producers to be easily mashable. Whatever the way that we adopt to measure the degree of modification, what we get is that malsters produce, invariably, a malt which is easy to mash and requires no protein rest no matter what.
The problem is now to understand why there are so many recipes around which still call for a protein rest, and some brewers appear to do that in their practice. Is this just a fossile remnant of past practices, "I do as my grand-grand-mother did because I trust her recipe", paying homage to a tradition for the sake of it, or is still there, in 2021, some real sense and consequence in making a protein rest?
Which is to say: If we forget the definitions of "well-modified" malt and "under-modified malt", and get to the cathegories of "normally modified malt" and "less-than-normally modified malts", where "less than normally" means a Kolbach index of 35 or maybe 36 at the left margin of the fork, does it make any difference, for a less-than-normally modified malt, to make a protein rest? Is there any paper or test which attempted at make two beers identical in every respect except for the protein rest, and then examine the differences in taste, clarity, head retention, shelf durability etc?
Another doubt arises from reading this: The Oxford Companion to Beer Definition of Kolbach index
The reality is that the index is nothing more than a gauge of the extent to which proteolysis has occurred during malting. [...] It reveals nothing about the nature of the solubilized proteins and whether they are or are not problematic or beneficial.
Which can be read as "not all solubilized proteins are created equal and some are problematic" and, maybe, the protein rest is used by some brewers in order to solve those "problems" that would not appear by the simple reading of the Kolbach index.
I am very grateful for either answers or links to interesting sources.