In a fit of self flagellation, I brewed a Roggenbier today. It was expected to be a long day, and it was.
I did a step mash to try and deal with the glucans better, used a tsp of beta-glucanase in the mash and about 1.25 - 1.5 # of rice hulls. The mash flowed well through the first 2 steps and about 15 minutes of the 145 temp range and then as conversion started getting serious, it started to slow. I went from the 140's to 152 for about 45 minutes, then 158 and 170 to mash out for about 10mins.
Everything was pretty linear until 158; I added .5# of chocolate rye at 152 and raised the temp. I wasn't expecting any serious contribution but that wasn't the big surprise. I let the malt pipe drain for about 10 minutes after the mash out, and had about 5.25 gallons in the kettle, meaning I'd need about 3 gallons of sparge water for my eventual 6.5 gallon post boil volume. I did the sparge quickly so as to keep the grains in the 170-ish temp range, 1 gallon at a time, and resuming the sparge when I could hear the draining slow. I took refractometer readings throughout and it just didn't make sense.
I lost practically no gravity at all during the sparge. My recipe needed 1.041 pre-boil, I was at 1.059 ( really 1.056, my refractometer is a touch optimistic ). Literally the same readings I got before the sparge. I took several readings. Denial, anger, bargaining, depression, and finally acceptance. Ok, I'll sparge in another .5 gallons and let it drain for a bit.
I was targeting 8.25 gallons pre-boil, ended up with 9 gallons, finally saw a hit on the gravity at 1.046, really 1.043, which is close enough for government work. Boiled 60m, boiled exactly 1.75 gallons as expected, took the gravity and h*ly cr@p - right on the money at 1.059 - which is really 1.056.
Pitched in the tilt, let it settle and ... 1.056. I ended up with about 7 gallons in the 14 gallon fermenter. A little more than expected so I'm hoping to keg about 4-4.5 gallons in a 5 gallon keg and the remainder in a 2.5 gallon keg.