Good info guys I will try the weight method. I should save this for a newbie when he want to learn................. Hey you want to learn how to do a Decoction........
Here ya go. These are my simplified instructions for the method.
DECOCTION, What is it?
Decocting is a method of multi-temperature mashing that utilizes removing and then boiling and reincorporating portions of the mash to raise the temperature. It is said that the method developed centuries ago in central Europe many years before the invention of the thermometer. Decoctions were also a way for these early brewers to deal with the poorly malted grains of the time and obtain good starch conversion.
WHY SHOULD I BOTHER?
Well, you don't have to if you don't want to. Unless specifically designated all modern malts are well converted and will mash successfully with a single temperature infusion. However, there are those of us in the decoction underground who feel that there are positive side effects on the taste of the beer which decoction mashing provides, not obtainable with other methods.
During the boiling of the mash portion (the decoction "pull") a couple of significant changes take place. First, the heat and mechanical action of the boil break down the granules of starch making them more easily accessible to the conversion enzymes. This breakdown of starch particles will usually mean that a decoction yields a bit more conversion efficiency than an infusion mash on the same malt.
Second, via the Maillard reaction sugars and proteins undergo a process that creates melanoidins and other tasty compounds. This is very similar to what happens when sugar is caramelized in a saucepan or a steak is grilled. These melanoidins provide the subtle enhancements in flavor and color that only a decoction can give you.
HOW DO I DO IT?
You will need a decoction vessel, a stirring tool and a burner, preferably with an accurate flame control. The decoction vessel can be any non-reactive cooking pot large enough to comfortably hold the pulled mash. I use a 20 quart stainless steel stock pot and a large wooden spoon to stir. A scoop of some kind will also be needed to remove mash from the tun. I find a plastic-handled stainless steel strainer works well. A small pan or ladle can be used but a strainer allows the liquid to easily drain from the pulled mash when scooped.
Mashing in thick with a decoction is the way to go. I use a 1 Qt: 1 Lb water:grain ratio. The mash will thin out as you go and chances are you will add some water during the process. With a 1:1 ratio the total weight of the mash will be 2/3 water and 1/3 grain. For me this simplifies measuring the amount of mash to be pulled for decoctions. The ROT is 1/3 of the total mash by weight but in practice a little more, say 40%, is what I generally use.
Commercial breweries doing decoctions use steam heated kettles. The direct flame of a homebrew system does increase the chance of scorching and burning, things to obviously avoid. To take out some anti-scorch insurance I like to start the decoction vessel with a couple of quarts of water and bring it to the boil. This also adds a little bit of a heat fudge factor as you may be likely to undershoot your temps some on your first try. It is also probably a good idea to have both boiling and cold water on hand for quick emergency temp adjustments.
Most of my decoctions are "singles" with a short protein rest at ~130F for 15 minutes and then a jump to sugar rest ~152F for 60 minutes. A decoction to mashout is usually added at my brewery too. Typically the rise in temperature from a decoction will be 20 to 22 deg F although YMMV. Once you get the hang of it you may be surprised how accurate the temperature steps can be. Of course if you wanted to do more steps just start at a lower temperature. The "ultra traditional" historic decoction would be mashed in with cold water and proceed to acid rest, low protein, high protein and sugar rests. I've never gone this far but I have done a couple starting at the acid rest temperature of 95F.
OK you've mashed in and you have the decoction vessel ready. Pull 1/3 to 40% of the mash by weight taking as little liquid as possible and add it to the decoction vessel. Keep stirring CONSTANTLY even if you have started with a little water in the pot. Almost immediately you will start to see the color of the decocted mash darken, this is normal. Also don't worry about the beer being too dark. A double or even triple decoction with pils malt still will make a beautiful light colored beer. Keep stirring and don't forget to check the temperature. When the decoction reaches the next rest temp turn off the heat, cover and let sit for 15/20 minutes.
After resting the decoction add more heat and continue stirring until the whole thing starts to boil and bubble. (you can also do a short rest at mashout temp if you want to go nuts) Keep stirring and boiling for at least 10 minutes, more if you want. I usually do 25 to 35 minutes. Kill the heat and immediately add the boiled mash to the mash tun. Mix and stir thoroughly until the temperature is uniform. If the stars were aligned you will be right at your target temp. If not you can adjust down with cold water. If low by only a degree of two leave it or add some boiling water to adjust. If the temp is way off on the low side you probably got scared and didn't pull enough mash for the boil. In that case just pull some more, bring it quickly to boil and dump it back into the mashtun.
That's about it. Everything else you do is just like any other brew.
