There’s been a lot of discussion lately about consistency from batch to batch. A lot of you are using cooler mash tuns (I think) and just adding 10 to 15 degrees onto your strike water temperature and then just throwing in your grain immediately after adding the water. If we are to hit our target mash temperature and therefore add consistency to make better beer, how are we going to consistently hit our mash temperature especially if we are varying our grain bill and mash ratios. So I spent a little bit of time putting together a spreadsheet to possibly make hitting our target mash temperature a little easier and more consistently. I know brewing softwares can calculate these things for you, but you have to figure out a thermal mass which doesn’t seem altogether that straightforward.
Below is a picture of that spreadsheet. It requires a bit of trial and error in that you need to mash a handful of batches at the same grain bill and mash ratio to nail down what heat your cooler typically absorbs. I created a heat value called the BTU (Brewing Thermal Unit). Let’s say you brew a handful of batches that are all 11 lbs of malt and 1.3 mash ratio. You find that 10 degrees need to be added to your strike temperature to warm that cooler up. You input these values into the spreadsheet and get a BTU needed to heat up the cooler MLT (BTUCMT). For my cooler, it looks like that number is 143 BTU’s. This number is then used to figure out how many degrees need to be added to your strike water when you end up doing a batch with different grain bills and mash ratios. Let’s say you want to mash in 15lbs at a 1.6 mash ratio. Instead of adding 10 degrees to the strike water temperature, we now see we only need to add 5.9 degrees.
Hopefully, the spreadsheet shows up below for you all. I am not seeing pictures with the new forum format. Hopefully, we’ll figure it out.