The title may have tipped you off about the topic of today's post: the changes in the fermentability of wort due to various factors in the process of malting and mashing. A fascinating suubject, I'm sure you'll agree. With lots of details about dextrin.
Lott starts by summarising these factors:
"In order to emphasise the importance of a careful consideration of the effect of:—
A. Kiln heats on Malt,
B. Initial heats in the Mash-tub, and
C. Thick and Thin Mashes,
I have given in Table II certain figures which I will ask you to consider for few minutes in connection with the production of the most
suitable ales for bottling purposes.
Table II. A. Effects of Kiln Heat. Under cured. 160º F. Pale cured. 180º F. High dried. 225º F. Extract = dry solids, per cent. 68.6 67.6 62.8 Total sugars 72.5 63.7 54.5 Dextrin 13 21.5 32 Inactive matter 14.5 14.8 13.5 100 100 100 Ratio: Total sugars/Not sugar 2.6 1.7 1.2
B. Effects of Mash Heal on a given Sample of Malt. 148° F. 152° F. 156º F. Extract = dry solids, per cent. 75.3 74.8 74.6 Total sugars 86 80 74.6 Dextrin 2.7 9.9 15.6 Inactive matter 11.3 10.1 9.9 100 100 100 Ratio: Total sugars/Not sugar 6.2 4 2.9
It is evident that the most marked result of the increase of curing heats is the increase of the unfermentable or slowly fermentable dextrin, and the proportionate decrease of the readily fermentable sugars, so that high-dried malts yield a less fermentable extract than low-dried ones. This is perhaps more evident in the figures given in Table Ia."
Journal of the Federated Institutes of Brewing, Volume 7, Issue 2, March-April 1901, pages 202 - 203.
I've found high-dried malt very elusive. Sometimes it appears to denote very highly-kilned malts such as brown or amber malt. At others, just a version of pale malt kilned at a higher temperature. You can see the difference in the sugar composition of standard pale malt and high-dried malt. Crucially, the dextrin content was about 50% higher in the latter. No surprise, then, that the wort from high-dried malt was less fermentable. Mashing at a higher temperature also increased the dextrin conrtent at the expense of easily-fermentable sugars.
It's easy to see why a Mild Ale brewed from high-dried malt and mashed at a relatively high temperature would have a higher terminal gravity than a Pale Ale brewed from standard malt and mashed low.
"Another experiment gave the diastatic activity of three samples of the same malt:—
A. Partly cured, i.e., 2nd day on kiln = 56.9 Lintner.
B. Pale dried at 80º = 33.5 Lintner.
C. High dried at 220° = 11.1 Lintner.
The characteristic flavour of high-dried malt is not the only important feature which analysis fails to emphasise; there are certain caramelisation products which have a marked effect on the palate fulness of ales brewed with high-dried malts not nearly so evident in pale-dried malts, and almost entirely absent in undercured malts. The initial heat of the mash when the water is first extracting the soluble part of the malt is of the greatest importance in determining the ultimate composition of the wort, as in the first place it is this temperature which decides the quality of the diastase first extracted, and in the second place the action of that diastase on the starch cells of the malt.
The figures given are very conclusive; again a higher temperature increases the proportion of dextrinous matter, decreases the readily fermentable matter, and at the same time the soluble inactive matter to a slight extent.
Journal of the Federated Institutes of Brewing, Volume 7, Issue 2, March-April 1901, pages 203 - 204.
This section is, for me, very important. It shows that high-dried malt was retained diastatic power. Is 11.1º Lintner enough to convert itself? I'm pretty sure it isn't. I think somewhere around 30º Lintner is needed. Which means high-dried malt couldn't be used as a base malt.
It sounds as if high-dried malt would add body to a beer in two ways. Firstly, there were the "caramelisation products" created during kilning at a high temperature. Then there was the higher dextrin content which, not being readily fermentable, would also add body. Again, this shouldn't come as any surprise.
Finally something I've never considered much: the consistency of the mash.
Journal of the Federated Institutes of Brewing, Volume 7, Issue 2, March-April 1901, page 202.
C. Effect of Lengths. Thick mash. Thin mash. Extract = dry solids, per cent. 64 64.5 Total sugars 81.8 75.2 Dextrin 4.8 9 Inactive matter 13.4 14.9 100 100 Ratio: Total sugars/Not sugar 4.5 3
"The difference produced by increasing the proportion of water used in mashing is not so great as some brewers imagine, but the direction as shown in this extreme case, where double the volume of liquid is used in the thin mash, the initial being kept the same, is increased proportion of dextrin and decreased sugar."
Journal of the Federated Institutes of Brewing, Volume 7, Issue 2, March-April 1901, page 204.
As you can see, a very thin mash produced a wort with more dextrins. But, as Lott says, this is a very extreme example, and it's doubtful anyone adctually mashed so thin.
Next time we'll be looking at various example beers to see their composition in terms of fermentability. The we'll be done. I think.
Posts
6 comments:
How do these numbers compare to modern malts? Does any of this explain the high FG's seen in the old brew logs?
I wonder how Vienna and light and dark Munich malts compare to historic British high-kilned malts. I always use a fair proportion of dark Munich in my milds.
Edward,
yes I think it does at least partially explain the high FG's. But from other analyses in this article it seems that the real FG of some styles - all the Stock ones, basically - was considerably lower than the racking gravity, which is what appeard in the brewing records.
Jeff,
not sure how similar Munish malrs are. Are they kilned at a high temperature?
Ron - Yes, DeClerck says that Munich malt (not sure what color) is kilned at a final temperature of 105C for 5 hours, as opposed to 80-95C for pale malts. I use Durst dark Munich malt at 40EBC. They also make a 20 EBC. Both will convert themselves, and I use the dark at 100% for Dunkles.
"Jeff Renner said...
I wonder how Vienna and light and dark Munich malts compare to historic British high-kilned malts. I always use a fair proportion of dark Munich in my milds"
But the Germans will also be using multiple decoction mashes. That will effect colour and fermentability of the wort compared to the British standard infusion mash system
Post a Comment