I cranked out my 2nd BIAB on the weekend and was a bit disapointed with my efficiency.
The first brew one went pretty well, I followed the BIAB tutorial on this site, including the Schwartzbier recipe. Ended up with an OG of 1.050 which was south of the target but according to brewmate was 75%, which I thought was decent enough for a first attempt.
Second brew was a SMaSH with 5Kg of JW Trad Ale and PoR. Target OG for this brew at 75% efficiency was 1.052 according to Brewmate. I ended up with 1.040.
Grain was ground on the same mill with the same gap as brew one.
Differences in mash:
Brew 1:
Brew 2:
So where did I go wrong with brew 2? The main differences I can see are mash length, dough-in temp and amount of agitation. Which is likely to affect the efficiency most? I'll brew again this weekend with the same grain bill and see if I can do better.
Should mention I didn't have enough water for brew 2 and ended up with 19l into the fermentor the 1.040 was after diluting back to 23l. Brew 1 was pretty much spot on.
The first brew one went pretty well, I followed the BIAB tutorial on this site, including the Schwartzbier recipe. Ended up with an OG of 1.050 which was south of the target but according to brewmate was 75%, which I thought was decent enough for a first attempt.
Second brew was a SMaSH with 5Kg of JW Trad Ale and PoR. Target OG for this brew at 75% efficiency was 1.052 according to Brewmate. I ended up with 1.040.
Grain was ground on the same mill with the same gap as brew one.
Differences in mash:
Brew 1:
- 90 minutes at 66C
- Grain in at flame on, stirred continuously until mash temp reached - mainly to stop the bag burning on the bottom of the kettle
- Temp wasn't too stable as pot wasn't insulated, got down to 64 after 40 minutes, I heated back to 66, was down under 64 again by end of mash
- Regular agitations for first 40 minutes as per schedule in tutorial
- Grain out at 90 minutes, drained and squeezed bag in bucket and added extra wort back to kettle.
Brew 2:
- 60 minutes as 66C
- Didn't get the grain in until water was about 50C, stirred from then until mash temp reached
- Insulated pot with old sleeping bag, Temp was maybe 65 at end of mash.
- Only agitated once at 30 minutes as wanted to keep the pot wrapped up.
- Grain out at 60 minutes, drained, squeezed etc.
So where did I go wrong with brew 2? The main differences I can see are mash length, dough-in temp and amount of agitation. Which is likely to affect the efficiency most? I'll brew again this weekend with the same grain bill and see if I can do better.
Should mention I didn't have enough water for brew 2 and ended up with 19l into the fermentor the 1.040 was after diluting back to 23l. Brew 1 was pretty much spot on.