First attempt - what did I do wrong?

[DaddyLouLou]

I made my first attempt at BIAB yesterday, after graduating from kits. It didn't go quite to plan.

I was trying a recipe like this:

BIAB #1 (Special/Best/Premium Bitter)

Original Gravity (OG): 1.046 (°P): 11.4
Final Gravity (FG): 1.012 (°P): 3.1
Alcohol (ABV): 4.52 %
Colour (SRM): 6.2 (EBC): 12.2
Bitterness (IBU): 31.0 (Average)

88.89% Maris Otter Malt
5.56% Amber Malt
5.56% Torrified Wheat

0.9 g/L East Kent Golding (4.7% Alpha) @ 75 Minutes (Boil)
0.9 g/L Fuggles (5.7% Alpha) @ 75 Minutes (Boil)
0.9 g/L East Kent Golding (4.7% Alpha) @ 10 Minutes (Boil)
0.9 g/L Fuggles (5.7% Alpha) @ 10 Minutes (Boil)
0.4 g/L East Kent Golding (4.7% Alpha) @ 0 Minutes (Aroma)
0.4 g/L Fuggles (5.7% Alpha) @ 0 Minutes (Aroma)

0.2 g/L Irish Moss @ 15 Minutes (Boil)

Single step Infusion at 66°C for 75 Minutes. Boil for 75 Minutes

Fermented at 20°C with Safale S-04

Everything seemed to be going OK, but...

I only got an OG of 1.036, and there was a hell of a lot of sludge in the kettle at the end of the boil. A lot of this sludge tried to make a break for it, and get itself into the fermenter.

So, any idea what I did wrong with the mash to come out so low, and should I have used more Irish moss to try to get the trub to flocculate a bit better?

[jaroporter]

kinda need to know what your expected volumes were at each point, and mash efficiencies. sounds like you either got a lower than expected amount of sugar out of the grains or you boiled-off less water than you expected. regards the kettle trub, the amount of irish moss is fine but the transfer method into the FV can disturb it. how are you doing that part?

well done for a first try, it's gonna be a tasty best bitter now instead!

[vacant]

After checking what jaroporter said, I add to make sure your thermometer is accurate.

What was the total weight of grain, volume of liquor at start, volume of wort into FV, dead space in boiler?

[jaroporter]

actually, vacant's comment about temperature reminded me - what temperature did you take that gravity reading at? was it corrected if hotter than 20C?

[DaddyLouLou]

It was 4.5Kg in total - 4Kg MO, and 250g each of Amber an Torry Wheat.

I started with 34L liquor into the mash, and got 21L into the FV. When I measured it, there was 2L dead space in the boiler.

The thermometer was accurate (until it fell on the floor during the chill ) and I was using an IR one as well (slightly less accurate). I have corrected for the wort being 24°C when I took the reading.

The transfer from boiler to FV was via hose from the tap at the bottom of the boiler. Using the immersion chiller, I had go the temperature down to 30°C, and it wasn't dropping any more, so I left it standing (with the lid on) for an hour or so, to let the temp come down a bit more.

[Oli1979]

You boiled a hell of a lot off in 75 mins. I would expect you to end up with around 26lites after boil.
Also when your saying a lot of trub was trying to get into FV, you need to open the boiler tap slowly to let all protein and hops to create a filter on you boiler mesh before opening it more.
When using an IR temp device, it measures the temp of the surface temp, which is always a lot warmer than the bottom of the vessel. If you used this device on you mash reading, it may have read 66'c, but at the bottom or centre of the vessel it could be 62'c or lower.
Its a learning curve and you just make mistakes along the way, I did. my first AG wheat beer went down the drain it was that bad!

[vacant]

Those figures look good.

34 litres,less about 4.5 litres left soaked in the grain = 29.5l

I reckon to boil off approx 4 litres per hour on one kettle element = 5 litres boiled off after 75m = 24.5l

2 litres dead space = 22.5 litres into the FV. You got 21 so a slightly more vigorous boil?

I don't believe with BIAB that temperature variation within the mash is as great as a normal mash, so my only remaining thought is that the grain clumped together, giving a poor extraction.

[jaroporter]

so with those figures it looks like you planned for a mash eff of 78% but only got 62%. don't know whether you did already but i stir the mash again at the end and raise the temperature to make sure i rinse as many sugars from the grain and make the wort less viscous to help the sugars strain out. or you could dunk the grains in another pot of water to "sparge" if extraction is low.

[DaddyLouLou]

So, put this down to a learning experience, and hope that the beer is drinkable when it comes out of the FV.

Thanks guys.

[andyCo]

I always add a 10min mash out at 75c, constantly stiring the grains until I hit 75 then let it sit for 10 mins.
Seems to do the trick for me .

Andy

[Beer O'Clock]

Always, ALWAYS mash out .

[DaddyLouLou]

Always, ALWAYS mash out .

Noted!

[YeastWhisperer]

A lower than expected extraction rate is par for the course when one is first learning how to brew all-grain beer.