I have an (only slightly) off topic question. I have been trying my hand at batch sparging for my last half dozen or so beers. Reading through some of the comments on this thread, I am wondering if I am doing it wrong.
When I batch sparge (I do two sparge additions), I completely drain the mash tun of the mash wort before adding any sparge water. I then divide the volume of my sparge water in half. I add the first half to the drained bed, stir and wait about 10 min. Then I recirculate and collect the run off. I then repeat with the second half of my water.
Should I be adding my first sparge to the mash (and mash water) before I take my first runnings? My tun is certainly capable of handling that for most beers. Or should I be draining before I take my first runnings? It seemed to me like that was the only way to accurately figure out how much liquid retention you're getting in the grain.
Then again, I have had a couple of beers recently that attenuated much more than I thought they should given my mash temp. I guess it's possible that I am not shutting down the enzymes when I drain my tun before adding any sparge water.
But I swear the method I am using is a knock off of something I got off Denny's website.
There are several ways to batch sparge. I will tell you my method...I feel like it is simple and reproducible.
1. Preheat MLT (70qt rectangle cooler with SS braid) with one gallon boiling water. Rock MLT to let water touch the sides of the cooler.
2. Slowly run off preheat water.
3. Heat strike water. I use +16 degrees (eg. a 153F mash equals 170F strike water. I know it sounds high, but it works)
4. When strike water is almost ready, check to make sure that MLT is not draining anymore. Close valve.
5. Add strike water.
6. Add grain. Dough-in.
7. Close lid. Wait three minutes or so.
8. Check mash temp.
9. Heat mash out water. I use beersmith to calculate a round number of gallons to raise the mash temp to 168F. eg. I usually use 1.5 to 2 gallons and then figure out what temp that mash out water needs to be, rather than the minimum amount of boiling water needed. This keeps me from having to measure 1.79 gallons for example.
10. At end of mash, add mash out water, stir and close lid.
11. From experience, I know my grain absorption is between 0.11 to 0.12 gallons per pound of grain. I use this number to estimate the volume of first runnings. For example, if I have a 10 pound grain bill and 5 gallons of water in the MLT (strike plus mashout), then I estimate I will run off 3.9 gallons. I need to collect 8 gallons, so I heat up 4.5 gallons of water to sparge. I usually add a half gallon to my estimate and then take sparge water out of the pot (rather than being short and having to add more water and then heat it up).
12. Vorlauf then collect and measure the volume and gravity of the first runnings, put on burner and start the boil.
13. Add the appropriate volume of sparge water to MLT (8 gallons - 1st runnings volume).
14. Stir then check temperature.
15. Vorlauf then collect 2nd runnings (no need to measure, I know exactly how much I will collect because that is how much I added.
16. Add second runnings to brewpot, stir, and check gravity.
Hope that helps.
Eric