In Defense of Decoction

In Defense of Decoction

Postby Tonedef131 » Wed Feb 29, 2012 12:48 pm

Repost from the old message-board as requested at Feb 2011 meeting.

As the resident decoction advocate, I figure I should state a case for this ancient process for those of you who have never tried it or have doubts. It's no secret that I am a huge supporter of decoction mashing continental style lagers and I've been decoction mashing all my German beers for years. I'll answer a few common questions and concerns, this way I can continue to add onto these throughout the thread as new questions arise.



Q: What is decoction mashing?

Decoction mashing is a traditional European method of lager wort production. Simply put it is the removal of a portion of the mash, which is then boiled or "decocted", and added back to the main mash to raise the entire grain bed to the next desired temperature.

Q: Who's idea was that?

The Germans of course! They were developed because brewers did not have two crucial brewing instruments: a thermometer and a controllable heat source. Although they didn't have a way to monitor temperature, they knew that water always boiled at the same temperature. With this knowledge they concluded that if they were to remove the same quantity of mash every time, boil it, then return it, they would accurately hit their next rest temperature since the mash being returned was always 100C. This is pretty clever, and the malt of that time also tended to have very hard ends that boiling would help to further break down resulting in increased extraction efficiencies.

Q: Doesn't that extract tannins?

Yes and no. Brewers are told to never sparge their grainbed above 170 or so, which is always the first thing that pops into mind when you mention boiling grain. This is true during the sparge because the pH has risen substantially after run off, but during the initial mash it's low enough to restrict tannin extraction. However, some tannins will still be extracted which is part of the reason "lagering" is still used and also makes it less important to watch the grain bed temps during sparging.

Q: Why would I decoct?

There is a lot of reasons to decoct, some of which are no longer significant and others that are still very valid today. Now that we have accurate thermometers, large metal pots, controllable heat sources and high quality malt we don't have to do a triple decoction just to make sure we end up with a properly converted product. However, decoction does add a few other things that are unattainable any other way and have become a critical part of central Europe's lagers.

I) Color. The first thing you will notice when adding a decocted portion back to the mash (especially if you boiled it for more than 10 min) is that it's substantially darker than the rest of the mash, this is visual proof that melanoidins have been created.

II) Improved efficiency. Although the malt we have now is much better suited to mashing, boiling the grain will still knock some extra starch out of the grain which tends to make for a more consistent and sometimes increased mash efficiency.

III) Clearer wort/beer. Due to those extra starches being removed in the deco boils you will extract less unconverted starch out during the sparge, at which time there would be no enzymes left to convert it. You will also be breaking down proteins during the deco boils and knocking them out of solution.

IV) Enhanced malt flavor. This one is dangerous because when someone goes through an exhausting triple decoction mash they are expecting the beer to have a completely different flavor and a giant punch you in the mouth malt flavor. Now that wouldn't be very lager-like would it? What it does is slightly enhances the flavors of the malts that are present. This cannot be done any other way except by adding more of the malts themselves, which would make a completely different beer. Adding new specialty malts simply adds new flavors rather than enhancing the flavors that are already present from the base malts. Some Brumalts such as Melanoidin malt do increase maltiness, but that is by adding new malt flavors not increasing the ones that are already there, so again this is not a substitute for decoction. Do not add crystal malts to simulate a decoction, there is no caramelization during a decoction just melanoidin production so that is adding inappropriate flavors to the style and also can result in a sweet lager.

V) Full body and mouthfeel, without sweetness. The hallmark of most lagers is their dry finish, yet rich fulfilling mouthfeel. This cannot be achieved with single infusion mashing, the only thing you can control with a single infusion mash is how sweet and dextrinous the beer will be. For this reason in order to have a rich full mouthfeel, you will also have an underattenuated beer. With a decoction mash you can get the correct body from protein manipulation and sill have the proper level of attenuation and dryness.

VI) It's a great way to differentiate your beers. Until relatively recently breweries malted their own barley which obviously made for very distinct and varied beer from brewery to brewery. Now that malting has become its own industry, beers have become much more standardized and similar to one another. Decoction mashing is a good device to keep in your toolbox when you are looking for that little something extra to make your beer stand out.

Q: Which beers should I decoct?

Traditionally any style that originated in Germany, Bohemia or Vienna…although so long as you are using continentally derived malts you are free to experiment with it. It's most common in lagers, but some ales from the region may utilize less exhaustive forms of it. Although it's not a hard fast rule most of the time lagers should be triple decocted, Weizenbiers double decocted and stuff like Alt and Kolsch can be single decocted if you want. I find triples aren't worth the effort on ales partly because a lot of the flavor is covered up by the yeast but it's also something that was less traditional the further north from Bavaria you get. Bavarian wheat beers are the ales that benefit most from it, the wheat seems to respond well to being boiled and it lends a nice bready depth to them. Since you don't have any husks on the wheat to extract tannins from, deco mashed weissbiers seem especially creamy. I tend to think decoction flavors increase exponentially with successive decoctions. For example a single doesn't really give you substantial flavor differences, where as a double becomes noticeable and a triple is hard to miss.

Q: How do I decoct?

You basically have three options, you can do one, two or three pulls from the mash. Single decoctions are just a step mash up until the last step, which is a decoction bringing you up to mash out temperatures. Some people are fearful of this because any starch knocked out of the grain during this boil would not be exposed to enzymes for conversion since the whole mash will be near mashout temps once it's returned. I've done over a dozen single decoctions and never noticed this happening, but I've also never noticed much change in the character of the beer. Some breweries have adopted this method either due to equipment constraints or to save time while still claiming they decoct their beers. They obviously are a modern development, since you would need a thermometer to complete one, but I still do them on Kolsch because that's how I roll.

Double Decoction, or as the Germans call it Zweimaischverfahren, is by far the most commonly used form of decoction. They are still less common on dark beers, but since light beers largely outsell them you will find most brewers doing a double most of the time. I believe this is primarily because the first decoction on a triple takes forever, and by skipping that they save a lot of time while still getting some decoction contributions. This must have also come along around the same time as thermometers because the traditional schedule still calls for a dough in around 100F, then an infusion up to protein rest temps. These days most brewers in Germany are doing what they call Hochkurz which dives right into the protein rest skipping the lower dough in. I've found this to work just fine when using highly enzymatic malts, but would find the low strike in useful when dealing with higher kilned malts like Munich. Altbiers were originally double decoction, but most of the literature I've seen about them hints that brewers in Dusseldorf are pretty much all doing step mashes now.

As you might be starting to notice there is a lot of different schedules you can use and each brewer seems to have their own preferred one. I'll give a quick walkthrough of a basic, modern triple decoction schedule and if you are doing a double you can simply skip the first decoction, just make sure your water is the right temp to dough in at protein rest temps.

The notorious Dreimaischverfahren is the classic Bavarian three decoction mash that is still used to this day to create Dunkels, Bocks and even Munich style Helles. Plan to spend the better part of your day brewing when attempting one of these. As with all decoction schedules, I did this very much by the history books for a while and then started switching it up to cut out some steps I didn't find necessary anymore. I have actually found I like the product better when I cut out some steps, so rather than giving you a super historical one I'm just going to run you through a slightly simplified one that works better with todays malts.

Before I get into it I want to give a brief warning about scorching. I've only had it happen once and it was because I was doing 45min deco boils and it got too dry, but it tasted terrible and was horrible to scrape off the bottom of the pot. You don't have to stir it constantly if you have a quality pot and the right water ratio, but until after the sacc rest you are much more susceptible to it. Starches are not water soluble and will just fall to the bottom of the kettle where they will burn very quickly. Once the starches have been converted to sugars and become water soluble you have much less to worry about.

Strike in with water into an insulated mashtun to achieve 95-105F, the water ratio should be around 1.5qt/lb but you can go slightly looser for pale beers and slightly stiffer for dark beers. Pull 1/4 of the volume of the thick mash and put it into a thick bottomed pot with plenty of headspace, then heat it up to 129F range. At this point you can choose to cover it and do a 15 min rest, or continue to heat it up and skip the protease rest if it's not a protein dense barley type. Your next stop will be at 149F for another 15 min, and after that you can bring it right up to a boil. At this point you can boil for anywhere from 10-30 min depending on how much color and flavor development you are looking for. Once this is done dump it back into the main mash, stir it in and make sure it has settled into the continental barley protein rest range of 127-131. If it hasn't adjust with water then cover it up and wait 10 min before pulling the second deco. Now pull another 1/4 of the volume of the thick mash and take it up to boiling either very slowly (half hour) or stop at 162F for 20 min or until conversion is complete. Boil for 30 min, then dump it back in mixing to reach a temp of 146-151F adjusting with water as necessary. Cover the mash tun and give this 30 min before pulling the final decoction. This pull will be 1/3 of the mash and should be much thinner than the previous ones. Simply bring this to a boil and maintain that boil for 15 min. Mix this back into the main mash aiming for a temp of 164F, then let this rest for 30 min before beginning your sparge.

If that wasn't torturous enough for you, I've found authentic Czechoslovakian 3-mash schedules that have 22 individual steps and took me over 6 hours just to do the mash. I don't recommend this since most of the steps were designed to deal with lightly modified malts and VERY soft water, so it's a waste of time without both of them. If you are into Bohemian style lagers you can get away with using the previously outlined schedule, but there are a few slight changes to make it more authentic. First keep the main mash real loose, I usually do 2 qt/lb. Also the main sacc rest should take place at 144.5F and all three decoctions should be 1/3 of the mash, very thick and boiled for 20-30min. This will give you the rich color and chewy texture and flavor you are looking for out of a decocted Bohemian lager, just mind those thick deco boils as they can scorch if you aren't watchful.

Q: Doesn't that take a long time?

Absolutely. If you are in a hurry or the kind of brewer who is only doing it to save money you are in the wrong thread. For your average decoction brew day you are looking at about 8 hours, which is a long day but I can't think of a better way to spend a day than brewing beer and knowing I put all kinds of effort into something that few pros take the time to do. This is what hobbies are all about, getting obsessive and going overboard to make it the kind of precision product that you just can't buy from an industry trying to squeeze every last penny out of their product. Every time you decoction mash you are giving a giant middle finger to the neo-liberal economy that would never spend time and energy to slightly increase a product…as a homebrewer "good enough" doesn't have to be the top end of quality.

Q: But I love shortcuts and consumerism and I even brew in a bag made out of an American flag.

Perhaps golfing or firearm rallies would be hobbies better suited to you.

Q: I'm about to brew my first beer ever…should I decoct it?

Probably not, this is a method that takes some practice to master and contradicts a lot of what new brewers are told. Also, as stated before it has subtle effects and is for those brewers who are looking to get just that little something special out of their beers. Master the rest of the aspects of wort production and fermentation, then when you are already making good lagers and are looking for a way to switch it up come back to this thread. Although if you want some decoction flavors in you beer Weyermann produces a lot of their liquid extracts via decoction mash, see if you can track some of those down.

Q: Got any pro tips for people new to decoction?

I) Preheat your scooping instrument. If you dunk a cold saucepan or huge spoon or whatever you're using to remove decoction into the main mash it will drop several degrees. Stick it in a pot of very hot water for a few seconds first or you will drop way too low in your main mash while your doing your deco boils.

II) Keep an eye on the deco boils, especially before conversion. Scorching is real and if it happens you will not be happy with the resulting beer. Be sure to stir it often and use the thickest bottomed pot you can find. This tends to only happen when the mash is too thick, so make sure you start with a proper amount of liquid in the pulled mash and if you are doing a long deco boil don't be afraid to add a bit of water part way through to thin it back out.

III) Keep it pretty thin. 1.5-2.1 qt/lb seems to be the standard when decoction mashing because it's an easier mash to work with. Plus most of the enzymes escape into the liquid so the the thinner the mash is, the more will be retained despite you nuking a bunch in the deco boils.

IV) Don't try to do a decoction with American or British malts. They are overmodified and nearly stripped of all their protein and are created exclusively for single infusion mashing.

V) Condition your malt with water. Nowadays German brewers wet mill but in centuries before that was available they conditioned their malt by hand. It's really easy to do and although it's not necessary when doing infusion mashing (unless you're having runoff problems) it becomes more important when decoction mashing. Husks will have a lot less surface area and exposed ends after conditioning that will further reduce tannin extraction during the deco boils.

VI) Rise rates don't really work well for homebrewers. If you see classic schedules a lot of them just do a very slow rise up to the boiling which takes the mash gently through all the rests. With the quantities and heat sources we are typically dealing with that doesn't work very well, which is why we use the short rests on the decocted portions. If you wanna try it you will need an extremely gentle heat source, lots of patience and you will also have to be constantly stirring it to evenly distribute the heat.


If after you have done a dozen or so multiple decoction mashes and still think they are a waste of time I'd recommend you call up Paulaner, New Glarus, Weihenstephaner, Victory, Pilsner Urquell, Stoudt's, Spaten, Gordon Biersch, Bitburger and Samuel Adams to let them know they are brewing their lagers incorrectly. Perhaps they would appreciate you saving them so much time and energy that they will send you a free T-shirt.
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Re: In Defense of Decoction

Postby derekburgette » Sun Mar 04, 2012 11:34 am

From some reading and listening I thought all malts are modified these days making it more of a traditional method to decoct. From reading this, it doesn't sound like that is necessarily true. Is it just certain types of base malts? I haven't decocted, but would love to do a Helles some day.
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Re: In Defense of Decoction

Postby Tonedef131 » Mon Mar 05, 2012 1:25 pm

derekburgette wrote:Is it just certain types of base malts?


The term modification is sort of a misnomer. It refers to how much the maltster let the barleycorn grow before kilning it to lock in the level of protein manipulation. When barley sprouts in the earth it splits up the proteins into amino acids used for plant growth and enzymes used for starch conversion (food/glucose production). So the more modified barley is, the less protein it has since it's already been used for other things. However, it also depends on the barley that the maltster starts with and how the seed scientists have designed it to be.

How does this effect a brewer? Well for one the more modified, the more enzymes it has and the faster conversions will happen. This is obviously desirable in enormous breweries like AB, Sierra Nevada, Coors, New Belgium, and Miller because time is money and the faster they can get a batch out of the mashtun the faster they can get the next one in and the faster Bros can get drunk while watching the game. These brewing giants tell the barley farmers to grow varieties that are little sugar batteries with just enough protein to be turned into enzymes, that way they get more sugar extraction per given weight of malt. This is why different base malts have different extractions potentials and also why US 2-row base malt is used by most breweries in the US, because it's the most mass produced therefore the least expensive.

Capitalism +1
Homebrewers +0

So no, you should not use a protein rest on American malts because they are intentionally made from protein light barley and modified to the point where a protein rest would be detrimental. This type of barley is perfect for your American beers, it's protein deficient and flavorless. This allows for extra dry lagers with no body which are obviously popular, and hop bomb IIIIIPAs where you don't want any malt flavor and rely on residual sugars for the body.

The other side of the coin comes into play when you want to start making continental style beers which rely on proteins for body and mouthfeel. These also tend to be more malt focused with much less reliance on specialty malts, so the flavor and character of the base malt becomes much more important. For these you want to use a continental derived malt because they are not genetically modified to contain less protein/more sugar and are modified to the point where you can still do a protein rest to control the level of peptide bond debranching.

Recap: like most things in brewing, there is no one catch all mash that should be used on every beer style. Your best bet is when brewing a style, use a malt and a mash that derived from that region. For example, the British overmodify their malts and therefore never do anything other than a single infusion so neither should you when using British Malts. The Germans make malts fitting the styles of beers they brew and do step/decoction mashes. Therefore, when attempting to make an authentically German tasting beer, I would use a German malt and mash.
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