Wednesday 4 June 2014

Dextrin and decoction

Busy, busy, busy. That's my life. Gallavanting around the world trying to sell my book. Sometimes it gets in the way of my other work.

I found these fascinating analyses of different mashing methods just before I left for San Diego. No time to write about them then. "I'll do it when I get back." I thought. That was before a random Truman document led me astray. I've only just remembered about the mashing stuff.

When I first looked seriously ay decoction mashing in my early blogging days, I was surprised to discover just how many different methods there were. One made a particular impression on me: the Satz (or Augsburg) method.

In it, the malt is mashed in with cold water and left to sit for four or five hours. The liquid which accumulated below the false bottom, called Satz, was drawn off. It contained various stuff from the malt but, most importantly, some of the enzymes.

It's one of the methods which crops up in the article in "Jahresbericht über die Leistungen der chemischen Technologie" which appeared in 1868. There are six mashing schemes considered in total. But, frustratingly, none of them are explained. I think I know what infusion is, but what about decoction or Bock? As I just mentioned, there are very many different types of decoction. Which one do they mean?

A couple of different tables appear in the article. First is the composition of the wort:

Worts
decoction Bock Satz method so-called English method with added starch infusion
sugar 4.85 7.10 4.37 5.00 5.31 5.26
dextrin 6.24 8.60 7.61 7.70 6.23 6.68
nitrogen-containing substance 0.79 1.35 - - 0.67 -
other contents 0.41 0.63 0.95 0.80 0.22 0.70
specific gravity 1050 1073 1052.7 1055.1 1051 1051.5
extract (directly measured) 11.87 17.05 11.98 12.70 12.30 11.94
extract according to Balling 12.29 17.68 12.93 13.50 12.52 12.64
Source:
Jahresbericht über die Leistungen der chemischen Technologie, 1868, page 543.

Next the composition of the beer after fermentation:

Beer after tub fermentation
decoction Bock Satz method so-called English method with added starch infusion
alcohol 2.81 3.38 2.94 2.96 3.03 3.13
sugar 1.58 2.32 1.46 1.68 1.59 1.33
dextrin 4.61 6.91 4.77 5.26 4.56 4.80
nitrogen-containing substance 0.38 0.74 - - 0.44 -
other contents 0.38 0.4 0.89 0.97 0.14 0.55
specific gravity 1022.8 1042 1028.6 1031.8 1027 1026.8
extract (directly measured) 6.57 9.98 6.23 6.93 6.59 6.13
extract according to Balling 6.95 10.38 7.12 7.90 6.73 6.68
Source:
Jahresbericht über die Leistungen der chemischen Technologie, 1868, page 544.


And finally one showing the relationship between the sugar and dextrin content in both the wort and finished beer.

for each unit of sugar
mashing method dextrin in the wort dextrin in the beer
with added starch 1.170 2.868
Bock 1.211 2.979
infusion 1.270 3.609
decoction 1.286 2.918
so-called English 1.540 3.137
Satz 1.740 3.267
Source:
Jahresbericht über die Leistungen der chemischen Technologie, 1868, page 544.

I have to admit that these don't show what I would have expected. I'd have bet that the infusion mash would produce the least dextrin. But that's not the case. It actually places about in the middle of the pack.

In the last table the Bock method comes quite low down because of the high density of the wort and the poor degree of attenuation. These both mean that there are relatively high levels of sugar both before and after fermentation.

It's fascinating, even though I'm not sure exactly what it's telling me.

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