Decoction Mashing - Decoction volume

[BugAC]

I do partial decoction mash (hochkurz) occasionally when i brew some of my lagers. Hochkurz mash is essentially your first step is around 144 - 146 for 40 minutes (about 12-13 qts), then you decoct about 3-4 qts (5 gallon batch) for 20 minutes, then add back to get your mash temp up to 160. However, i find that only 4 qts (1 gallon) of boiling wort added back does not get my temps high enough for the final step. I consistently get about 156 degrees after adding in. Does the decocted amount affect the mash/beer if i increase the amount?

For a czech amber lager, i adjusted my hochkurz temps. 150 for primary rest, then decocted 2 gallons of wort and boiled, then added back that got my temps up to 162, and let that sit. Intent for the higher temps is i didn't want the beer to be as dry. Overall the beer was very good, and it received a 2nd place medal in it's style category and scored a 39/40.

 

[hottpeper13]

When I decoct I separate the grain from the wort with a strainer and put the grain in the kettle to decoct. I strike at 143* rest 10 min then pull my decoction. I use as much grain as I can then add back until tun is at 158-160*, if not all grain is needed I let sit until at tun temp then incorporate it. After the sac rest I drain some wort into the BK, boil and pump back to get to 172* for mashout and foam stability.

 

[IslandLizard]

As @hottpeper13 said, you boil the thick part of the mash, pulling out about 1/3 to 1/2 the grist. You'll get a feel for the amount of clinging wort needed when scooping it out, it should be a stirrable thick porridge.

I strike at 143* rest 10 min then pull my decoction. I use as much grain as I can

You don't have any conversion issues using that much of the grist that early on in the mash? Decocting only 1/3 to 1/2 of the grist is more of the standard isn't it? Especially when decocting early in the mash, me thinks.

 

[hottpeper13]

After pulling the grist I raise the temp to 160 and hold for 30 min, then boil. Most times I'm over my expected OG by a couple points. Enzymes aren't like starches and go into the wort before starch is gelatinized. It takes over an hour to get the first one done and the 143* wort in the tun is converting the whole time.

 

[jerrylotto]

I do a step mash (100F, 125F, 143F, 152F, mashout) when I decoct (typically a double) starting with 1/3 of the mash (mostly grain but not strained) at the start of the 143F step which I first heat to 152F and hold for 10-15 min before bringing to a boil. After I return this to the mash tun, I'm generally around 152F for the final step. The second decoction of 1/3 of the mixed mash is just boiled and brings the whole thing up to 165F when returned to the mash (mashout) after which I sparge at 170F.

 

[hottpeper13]

If I'm using floor malted grain I strike at 122* with a 1:1 qt/lb then add boiling liquor to get to ~143*. This ramps me up right away so 20 min is only 20 min. The mash is now loose enough to get the grain out easily.