I’m brewing a coffee stout for a friend who owns a coffee shop. He would like it for a Christmas party so I needed to brew it ASAP. I mashed in at 1:00pm 50 qt. Rubbermaid square picnic cooler. I pre heated the cooler with 1 gallon boiling water.
10lbs. grist,12.5 quarts of 170 degree water. Temp settled at 153.2 Bath towels underneath, completely drapped with 10 more bath towels. I went back to work.
Temp after 4 hours was 143.4. I was surprised with the amount of the temp. drop indoors.
Added 1.5 gallons boiling water 10 minute rest, temp. rose to 160. First runnings 1.066 2.75 gallons. added 3.50 gallons of 170 degree water ab nd drew off 3.75 gallons, final runnings 1.014. Pre boil Gravity was 1.037 post boil was 1.046 5 gallons to fermenter.
I hit my numbers spot on per Beersmith except for a slightly lower final volume, and short on first runnings. Fermentation started within 4 hours using a 1 liter starter. All else held constant I’m pretty satisfied, but that temp. drop seems like alot.
Please critique.
That a pretty small grain bill for a large cooler. I’m not surprised with the temp loss. But you should not have much of an issue with it.
It’s possible the cooler didn’t fully heat up.
I heat all my mash water to 170* and add the to the cooler. Allowing the temp to drop to 160. Then add the grain. Stir till the temp drops to 150*.
You added 3.5 gallons for the 2nd runnings but received 3.75. Looks like you made up for the low 1st runnings?
Is your lower volume the preboil or post boil? If you had what you wanted preboil, then you had better boil off rate than normal or boiled longer than normal. You just need a little more water to account for this.
Agreed. 1 gallon of water doesn’t sound like enough to heat that large of a cooler. It’s only going to heat the part that it is in contact with well. Also, the large head space will wick the heat away. You’ll want to minimize the head space to hold the heat in.
Yeah, one gallon isn’t enough. I mash in a 48 qt Igloo Ice Cube, so my MT is comparable to yours. What I do is heat the strike water about seven to ten degrees above my desired temp and let the water cool to my strike temp. How much above depends on the volume of strike water and the ambient temp in my brewing area. I brew in my garage and find it also helps to bring the MT into the house overnight during the colder months.
Thanks for the suggestions. In going back over my notes I have been losing on average 2.1 degrees f. for a 1 hour mash. So if I’m not mashing overnight and doing the standard 60 to 90 minute mash and my target temp is 152. Do I start at 154 and end at 152ish or start at 152 and end at 150? If I’m over thinking this feel free to tell me so, because mash temps. seem to be one of the most important factors in getting a consistant quality. Thanks.
IMO you are over thinking this. My guess is there are warmer and colder spots inside the cooler. No matter how hard we try to stir and get it even.
Pick one process and work with it. If you think the beer is not turning out like you want, increase/decrease the temp.
I shoot for the temp I want at the start. If the temp drops over the hour, oh well.
[quote=“Nighthawk”]IMO you are over thinking this. My guess is there are warmer and colder spots inside the cooler. No matter how hard we try to stir and get it even.
Pick one process and work with it. If you think the beer is not turning out like you want, increase/decrease the temp.
I shoot for the temp I want at the start. If the temp drops over the hour, oh well.[/quote]
Well said! Losing 2F over an hour is NOT a big deal.
The slides from the attenuation talk at NHC seem to point that from 146-155 that attenuation is pretty even. I’m not sure how that factors into taste and mouth feel but it goes against the normal thinking. Mashing at 153 gives you the most attenuation in the above range when I was always told that 152-153F gives you more body.
