I'd already made a recipe up on hopville/beer calculus;
Malt and fermentables
% KG EBC Yield
81% 2.25 Marris Otter (Crisp) Mash 6.4 %
9% 0.25 British Crystal 70-80LMash 123.8 %
9% 0.25 Brown Sugar, Light Boil 13.1 %
1% 0.014 Chocolate Wheat Malt Mash 661.0 %
2.764
Specific Gravity 1.069 OG (1.061 to 1.072) 16.8° Plato
1.019 FG (1.016 to 1.020) 4.8° Plato
Measured Values
Color
30° EBC
15° SRM
Light Brown to Medium Brown
Mash Efficiency
75 %
Hops
Usage Time Grams AA » IBU
boil 60 min 14 Nugget ~ pellet 11.4 » 35.9
boil 15 min 10 Fuggles ~ pellet 4.1 » 4.6
boil 15 min 10 Kent Golding ~ pellet 5.1 » 5.7
boil 5 min 8 Fuggles ~ pellet 4.1 » 1.5
boil 5 min 8 Kent Golding ~ pellet 5.1 » 1.8
Bitterness
49.4 IBU
ƒ: Tinseth
6 HBU
BU:GU
0.72
Yeast
Safale S-04 Dry Yeast
yeast in dry form with high flocculation and 73% attenuation
Alcohol
6.7% ABV
5.0% ABW
Calories
228
per 12 oz.
I had a quick look at the BIAB calculator and saw that to reach my desired post boil OG of 1.068 for a 10.00ltr brew length I'd need somewhere around 3.45 kg of grain and about 18 litres of water (I changed the boil time to 60 minutes). I also couldn't figure out how to input, effectively, so that they'd change things or make sense to me, the fermentables in the grains section of the calculator.
I'm paying JP Yen 400 for 12 litres of bottled water, the tap water definitely has a chlorine/chloramine smell to it, and the Maris Otter, whole/uncrushed, is costing me JP Yen 65 per 100g, so things work out to be pretty damn expensive here. (I'm thinking more of the expense of a 5 gallon batch as opposed to this 2.5 gallon batch I'm doing) So, anyway,,,,I ended up winging things a bit
Went for it this last weekend. Started on Friday night,,,,,,,,,, late,,,,,,,, well actually started by milling/food processing the hell out of/pulverising my grains on Thursday night, but did the actual mash on Friday.
When I started filling my brew pot, got to about 14 litres, of the 18, in there and realised that there wasn't going to be any way I could get another 4 litres PLUS the grain in there so I started heating up the water and added my 2.514kg of Marris otter, 250g crystal 70 and 14g chocolate wheat at around 65C, heated up a bit and added another 2 litres or so of water, again heated 'til 69C, turned off the heat, insulated the pot and started the mash. I figured if I could keep in the range of 66 to 68 degrees, for the most part, I'd get a decent balance of fermentable and less fermentable sugars and hopefully strike a happy medium flavourwise. Had to apply heat a few times during the mash and I think the lowest it got was just above 65C (this is all assuming my cheapo thermometer is accurate. I did try it alongside another and both read the same but I didn't try calibrating in boiling or iced water). I dunked (opened bag, stirred the grains, getting lots of water movement around the inside of the bag, bobbing and sloshing the bag around in the pot) and squeezed the grain bag about 4 or 5 times. Considered trying a dunk sparge in some more water to make up for having been a bit under full volume of water for the mash, but didn't in the end.
Post mash or pre-boil gravity was 1.050 - 1.052, which I thought was bloody amazing, I'd said/thought to myself that anything near 1.048 would be quite respectable for my first attempt at BIAB and mashing grains.
Anyway, by the time I'd got this far it was about 3:00AM so I decided to knock it on the head for the night, cover the BK and get started the next morning.
Did a 60 minute boil the next morning with the above hopping schedule and, after cooling the wort down to about 22C, my measured post boil gravity was a touch over 1.068 , so I was, again, very surprised,,,, and highly elated
The other major point that struck me was that after I racked to the FV I'd managed to get nearly exactly the level of wort in the Mr. Beer LBK that I had shot for, so I must be close to 10ltr, and the volume of wort left in the brew pot with major trub was minimal, so I may have transferred some high particle content wort into the fermenter. Not really too worried about it though. Possibly I'll lose out on final volume to huge trub.
Rehydrated a pack of S-04 and pitched at 21-22C on Saturday, started getting an even, thin, 1/2 inch, krausen forming just yesterday so looking good so far and the ferm temp is now constant at 18C.
I suppose that my haphazard (mis)-adventure means that any chance of figuring out mash efficiency is kaput.
I really need a bigger pot as this one, that I thought was 20 litres so could at least accommodate a 10 litre BIAB, isn't as big as I originally thought and I reckon I'd like to be doing 19-21 litre, AG BIAB, or at the very least 19-21 litre partial mash with BIAB and full boil.
Anyway, sorry for the blabber. Just have to wait and see how the brew turns out. Still have another 2.25kg Marris Otter, about 500g crystal 70L, 86g of chocolate wheat and, depending on how this one develops I'll either do a PM @ 21 litres, or another go at AG (and a bit of brown sugar or Lyles Golden Syrup) @ 10(ish) litres again.
Cheers