botched step mash

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Well-Known Member
Dec 13, 2007
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So I tried to get fancy on my first all grain attempt and tried to do a two step mash. The recipe was for a Kolsch, so my plan was to do 140F for 40min and 158 for 20 mins to get a drier final beer. I was making the temp transition by infusing boiling water. The initial infusion went well, I was pretty much right on target.
I had a miscommunication with my brew buddy making the second infusion and accidentally added the 170F sparge water instead of the boiling water. Of course, I didn't hit my target second step temperature. It took a while to futz with adding more boiling water to raise the temp and with the extra water in mash tun, I could only get it to around 154F without thinning the mash too much. So my mash schedule turned out more like:

142F for 40min 1:1 ratio
148F for 15min 1.5:1 ratio
154F for 20min 2:1 ratio

Efficiency was actually good at 75%

So... what kind of effect will this likely have on the finished beer? Much drier?

P.S. Is the following logic correct? One of the reasons I did a two step mash is I thought hitting exact temperatures wouldn't be as critical as doing a single infusion because I'm not trying to control wort fermentability by balancing the alpha and beta temp ranges, and would instead be controlling my wort fermentability by time spent in the heart of each enzyme temp range, where the other enzyme would not be active at all.
It'll work, but try single step infusion the next time. American 2 row, Marris Otter or Belgian Pilsener is modified and will work well with a single step infusion mash. 150 for drier beers, 154 for maltier brews.