Hey Guys and Girls,
Just a few questions after my inaugural all grain brew day. But first, here are the vitals;
10 lbs Rahr 2-row
1.75 lbs Rahr 6-row
3.0 lbs Briess Carmel #20
Mashed in- 163F strike water with total volume of 6.5 gal.
Batch Sparged for 60 min with 3.5 gal @ 163F and 10 min with 3.0 gal @ 152F.
Boil Volume (initial): 5.5 gal.
Boil Volume (final): 4.25 gal.
Net Loss: 1.25 gal
1oz Magnum 60 min
1oz Centennial 20 min
1oz Amarillo 10 min
2oz Amarillo dry hopped
Target Og: 1.071 (while 1.071 is the stated Og on the original recipe, the grain bill was scaled up by 10% to account for loss of efficiency due to batch sparging)
Actual Og: 1.061
So, My questions are these. First, Is it common to lose over a gallon of water due to evaporation in the boil? I have a 1/2 barrel keg as my kettle and have a "snug" fitting lid. I'd used a propane burner which kept the wort at a violently rigorous boil. My sample showed excellent hot break, which is why I thought I had to boil so hard.
Next, I am concerned about my efficiency. I'd boiled past my five gallon mark so the Og should have been proportionally higher. Why is my efficiency so low, even after I added 10% to the grain bill? I used a "bazooka" screen tube in a coffin cooler with a march pump to vorlauft.
Finally, since I'd overshot my final volume I was wondering if anyone could provide me the calculation to determine IBU's as a function of hop's added, total volume, and possibly time in the boil (i.e. do the IBU's change due to the time in the boil?). Not to be a ass but I'd prefer the math and not a calculator.
Thanks a ton for any help I can get. This has been an awesome experience so far and I am looking forward to many, many more. Oh, and can someone point me in the direction of your best spring brew that can be fermented at room temp?
Faol saol agat, gob fliuch, agus bás in Éirinn, Sláinte!