Sunday, 16 November 2014

German brewing in 1966 - kilning

We're just about done with malting, thank god. I've been struggling to keep my eyes open.

First it's the kilns themselves:

"Kilning.—Most kilns are single units. In addition to automatic direct coke firing, one finds direct and indirect oil firing, in which case a suitably-designed furnace will avoid "magpie" malts. However, oil containers are expensive and the construction is connected with a series of difficulties, so that interest has been shown in a gas-heated kiln, particularly as natural gas and refined gas is available in considerable quantities, and it is expected that its price will approach the prices of other fuels. The content of methane in natural gas and of hydrogen in processed gas results in combustion of these gases to water, so the air has a reduced drying effect. As a result, a 10% increase in ventilation is necessary and, when re-circulating, the amount of fresh air will also have to be increased. In passing, it is noted that automation of a kiln is a very profitable investment."
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 17.

I wonder if they did go over to using natural gas? I'm pretty sure that it got cheaper in the 1970's and 1980's when supplies from Europe kicked in.

I wasn't quite sure what 'magpie' malt was, so I looked it up:

"High sulphur fuels, when burned, give rise to sulphur dioxide (SO2) and sulphur trioxide (SO3). One the one hand, these acid gases damage and corrode the kiln structure and add to atmospheric pollution. High levels may cause local discoloured marks on malt grains, producing 'magpie' malt."
"Malts and Malting" by D.E. Briggs, 1998, page 226.

It's what I had guesses - malt with two colours. But it's nice to have it confirmed.

Now it's about the kilning process itself.

"The various types of malt are kilned according to the beer requirements. For Pilsener and very light export beers a very pale but intensively kilned malt is required: colour, approximately 2.5° E.B.C.; protein modification, 37-40% Kolbach; coarse/fine grind difference, 1.5-2.0. Some maltings try to achieve a lower modification in order to improve the head of the beer. Even for the pale-coloured heavy beers (original gravity 16.5-17.5%) a very pale coloured malt is used."
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 17.

There's so much about malting I don't understand. Like why a lower level of modification helps head retention. I suspect British brewers wouldn't bother with that and would just throw in some wheat instead. Because of the weirdness of the Reinheitsgebot, that wouldn't be allowed in a German bottom-fermenting beer.

Here's what Briggs has to say about Lager malts:

"The palest of the European products are Pilsen malts (Pilsener Malz). In the past these were undermodified but now they are fully modified and are prepared from barleys having moderate nitrogen contents. They are kilned at low temperatures to minimize colour formation. Typical analyses are E, at least 81% (EBC, on dry), fine-coarse extract difference 1-2%; TN, 1.68 (10.5% protein); Kolbach index 38-42%; moisture less than 4.5%; -amylase 40 DU; DP 240-300 ºW.-K.; saccharification time 10-15 min.; colour, 2.5-3.4 ºEBC; boiled wort colour, 4.2-6.2 ºEBC; wort pH, 5.9-6.0. Helles (pale; light) malts are rather similar, but are made from barleys richer in nitrogen. British lager malts are all pale and well modified. Analyses are usually in the ranges: HWE 300-310 lº/kg (on dry), TN, 1.55-1.75%; TSN, 0.5-0.7%; SNR, 31-41%; DP, not more than 70 ºIoB; moisture less than 4.5%; saccharification time less that 15 minutes. Colour may be 3.0 ºEBC. Because of the low temperatures used in kilning lager malts (finishing curing at e.g., 70 ºC; 158 ºF) are rich in enzymes and so sometimes give slightly higher extracts than pale ale malts, which are cured at higher temperatures (finishing at 95-105 ºC; 203-221 ºF), and have more characteristic flavours but lower enzyme activities."
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, page 27.

Briggs says that the difference between Helles and Pilsner malts is the nitrogen content, while Narziss claims that they are a bit darker than Pilsenr malt:

"The West German export beers are somewhat darker. For these beers, as well as for the Bavarian pale-coloured lager beers, malt with a good modification and a colour of approximately 4° E.B.C. is required. Occasionally a certain percentage of "Wiener" malt with a colour 5.0-6.00 E.B.C. is used in the grist, although this malt is normally used for "Marzenbieren" (medium coloured beers). The dark Munich malts have a very wet and intensive germination and are kilned off at 100-105° C; as a result they obtain a good aroma. Owing to the lengthy kilning they are poor in enzymes and have to be mashed very carefully. They are used on their own, or together with approximately 1% coloured malt for the brewing of dark beer. For Marzenbiere they are blended to 50% with pale malt."
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 18.

That's interesting. The colour quoted for Wiener malt is a good bit lower than Weyermann's specification, which gives it as 6-9º EBC. One of the biggest difference between British and German brewing are base malts. In Britain you've only really got a choice of two: pale malt of pils malt. While in Germany you've also got Wiener malt, two types of Munich malt and smoked malt.

Nice of Narziss to quote some grists. Though he doesn't mention one of my personal favourites for a dark Lager. It's what Hofmann in Hohenschwärz uses: 99% Vienna malt and 1% Farbmalz. Do Munich breweries still use Munich malt as a base for the Dunkles? I suspect Paulaner do, though they may have brought that back. Last time I tried it there was the distinctive nutty malt flavour which I associate with Munich malt. I'm sure it hadn't been there a few years ago.

Here's Brigg's take on darker malts:

"In German practice the next type is Viennese malt (Wiener Malz), which is used for making `golden' lagers. This is made from normally modified green malt kilned to a final temperature of about 90 ºC (194 ºF), giving a colour of 5.5-6.0 ºEBC. Munich malt (MuÈnchener Malz) is relatively dark, very well modified and aromatic and is made by germinating nitrogen-rich barley, steeped to a high moisture content, so that it is well grown (all acrospires at least three-quarters grown) and finishing germination warm, at 25 ºC (77 ºF). Kilning involves some stewing and curing is finished at 100-105 ºC (212-221 ºF), conditions causing appreciable enzyme destruction. This malt has a colour of 15-25 ºEBC. The wort is rich in melanoidin precursors and darkens on boiling, e.g., from 15 to 25 ºEBC. Other typical analyses are: E, 80%, (on dry); fine-coarse extract difference 2-3%; total protein 11.5% (TN, 1.84%); Kolbach index, 38-40%; saccharification time, 20-30 min.; wort fermentability, about 75% (compared to wort from Pilsen malt of about 81%). -Amylase and DP values are low, at 30DU and 140 ºW.-K. respectively. Analyses of a British made, Munich-style malt are: HWE, 300 lº/kg, (on dry); moisture 4.5%; TN, less than 1.65%, TSN less than 0.65%, colour about 15 ºEBC and DP at least 30 ºIoB."
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, page 27.

I see that he agrees with Narziss about a finishing temperature of 100-105º C for Munich malt. And also tells us that it produces a less fermentable wort. Having looked at analyses of plenty of modern German Dunkles recently, and only four of tewnty four examples had attenuation of below 76%. So I guess most are using pils malt as base. I suppose this partly explains the rubbish degree of attenuation in 19th-century examples. They must have been producing even less fermentable worts back then.

He also agrees with Narziss about Wiener malt being around 6º EBC. Clearly Weyermann are getting it wrong.

Next time we'll finally be getting into the brewhouse.

1 comment:

Jeff Renner said...

Durst makes a 40ºEBC dark Munich malt that makes a wonderful Dunkel all by itself. I imagine this is much like an old style Munich malt because I think that brewers in the 19th Century would not have used farbmalz. I typically get 70% attenuation or so.