So on another thread about coolers, Denny posted a chart that showed the conversion temps and it got me to thinking, which isn’t always a good thing. Will your wort collected in a batch sparge continue to convert sugars as you heat it up through 158-160? If so, could you effectively do a Hockhurz type mash by heating the wort up and holding it at 158 for a few minutes before you head to the boil? This would help guys who worry about temperature loss in a cooler and don’t want to thin out the mash more with a hot water infusion…
Good question, I’m curious now as well.
An article in BYO a few months ago stated conversion still occurs in the kettle until a certain temperature but it didn’t indicate how much is occurring.
I think the answer is a definate maybe. Conversion will continue. I think starches tend to stay in the grain until they are converted into sugars, so there may not be many starches to convert in wort. Probably the bigger problem is that starches converted to simple sugars obviously can’t be converted back into complex sugars. So after an hour at low temp, raising to a higher temp won’t build the body back up unless there are unconverted starches.
Of course, this answer is mostly brain splatter.
Perhaps if you sparge hotter you would be able to carry more unconverted starches over to the kettle? There’s always the risk for tannin extraction, but keeping the proper pH seems to be the biggest key to avoiding problems.
Theoretically, yes. Since the enzymes are in the wort, not so much in the grain at that point, it will keep converting until you denature the enzymes. I don’t know how much difference it would make.
Good answer IMO!
I had a second thought on this and that is - if the cooler mash temperature were not held for the traditional “longer time frame”, but rather in the 45 minute range and “incomplete conversion” occurs, will the incomplete conversion allow for the complex sugars to be made from the starches at the higher temperature if the wort is then being heated into the higher range and held there for another 30 minutes? I may just try this out to see what happens…
More brain splatter (is that where the truncation “BS” is coming from?) :o
Yeah, that probably would happen to some extent.
Isn’t this a classic step mash? 145 for 40 minutes, 158 for 30.
Or do you mean the second step is in the kettle? Again, I don’t know how many of the unconverted starches carry over. I know a turbid lambic mash uses hot sparge water (200+) to dissolve as much of this starch as possible, since it’s desirable for lambic fermentation.
Yea, I meant the second step being in the kettle - just may try it as an experiment, but not likely a standard operating procedure for the future.
I think the rub might be trying to hold 158ish in the kettle. Less mass than the mash, so it seems like it would be more difficult to achieve a stable temp.
Mash out denatures the Beta. The alpha is still active.
[quote]Yea, I meant the second step being in the kettle - just may try it as an experiment, but not likely a standard operating procedure for the future.
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So the idea is to drain off via a batch sparge a bit early so you can bring the temp back up in the kettle?
I don’t see any problem with this - depending on your recipe, there may actually be hardly any starch left to convert anyway (as some have noted), but conversion will continue until either the starch is spent or the enzymes have denatured. I think if your’e careful, you can hold a roughly 158 degree temp for long enough, but it is easy to overshoot on the way up, so I’d cut the heat a bit early.
For the record, I recently ran a constant 160 degree mash in an attempt to get a more full-bodied (dextrinous) session IPA. It seems to have worked quite well - with a 1.046 OG finishing at 1.015 (3.9% ABV). Both beta and alpha amylase are active at this temp - for a while. The beta can’t hold out long, but while it’s working, it is working hard. I clearly had plenty of fermentable sugars in the final mix. (The “scary high” mash was inspired by the Lagunitas IPA recipe - of course I could have just used dextrine malt or maltodextrine, but I wanted to try to achieve this through the mash process itself). In short, if you do overshoot 158 by a bit, it probably won’t be the end of the world - and in your case, the beta amylase has already done its work, anyway.
The conversion of starches to sugar is dependent upon the enzymes accessibility to the starches, which in a fluid state, it’s very likely that most enzymatic conversion will occur within the first 20 minutes of the mash. Then whatever is left will eventually be converted during the rise in temp to mashout or sparge. Raisng the temp to 158F, will in essence, convert any residual unconverted starches via alpha amylase, which is probably a very small percentage of the converted starches at that point during the mash.