First BIAB complete - Questions:

[banjobrew]

(previously done extract w/ steeping grains)

I was aiming for an OG of 1.048 and ended up with 1.034 so that's an efficiency of 52%.

I didn't squeeze the bag. Should I be squeezing the bag?

Should I mix the mash at any stage or just leave it alone for 60 minutes?

I had a 5L boil-off instead of a predicted 3L, so I thought the OG was going to be higher than expected.

Any tips would be lovely,

Thanks.

Notes:

I have a 30L kettle with a 2500W element.

Citra pale ale recipe:
4Kg Maris Otter,
222g Crystal 140,
222g Cara-pils,
9g Citra 60mins,
18g Citra 10mins,
27g Citra Whirlpool.

60 minute mash temp: 66.2C (aiming for 66.7C for medium body)
00 minute mash temp: 66.1C

[Sorcerers Apprentice]

You'd need to give us your liquor/water volume also, but the first place I'd look would be at your grist, the advantage of BIAB is that you can have a finer grind without blinding the grain bed and so causing run off issues. The next place I'd look is did you mix in the grains by adding them slowly? As dough balls will reduce your efficiency due to all the grist not being in contact with the liquor.

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[banjobrew]

You'd need to give us your liquor/water volume also, but the first place I'd look would be at your grist, the advantage of BIAB is that you can have a finer grind without blinding the grain bed and so causing run off issues. The next place I'd look is did you mix in the grains by adding them slowly? As dough balls will reduce your efficiency due to all the grist not being in contact with the liquor.

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Thanks for the reply,

The grain came crushed and it was noticeably coarse.

26.11L for the mash and rinsed the bag with 4L so total liquor 30.11L
After grain absorption I had a pre-boil of around 23L (estimated as I've no sight glass)
18L into the fermenter (aiming for 21L)

[BrewDorg]

Which shop did you buy the grain from, out of interest?

[banjobrew]

Which shop did you buy the grain from, out of interest?

The Homebrew Company.

[Donny]

Squeeze those bags away man 

Fellow BIAB brewer here and I always squeeze the bag and ask for my grain to be very finely milled.

After I read this article I felt fully justified about bag squeezing;

http://brulosophy.com/2017/05/22/brew-in-a-bag-the-impact-squeezing-the-bag-has-on-beer-character-exbeeriment-results/

[TheSumOfAllBeers]

If you want to chase your efficiency learn to calculate it right: you need to measure your volumes right, ensure your hydrometer is reading right, and know the difference between extract efficiency and brewhouse efficiency. Most Brewers only care about their extract efficiency.

[Slev]

Some thoughts :

1: stirring is your friend here. A good stir at doughing in (as S A mentioned above, breaks up the balls) and a good stir every 15-20 mins. Bring the grain at the bottom to the top.  Get the sugars flowing, and keeps temp uniform. You may lose a degree or two overall, but the benefits are your process predictability.
2: mashing out isn't really needed, but it does increase the viscosity of the wort, and helps to 'rinse' the sugars from the grain, as it were. So,  for the 4l you used to rinse, having it at mash out temps would be ideal (this is spargeing). I leave the bag in while i raise the temp to 78c, and depending on time,
I may leave it for a few minutes, give a good stir, before raising the bag.  (use to stir constantly as i applied heat,  but have eased off a little, but it wont hurt).
3: You lost 7l to absorption, so it seems. By my cals, you should have only lost less than 3 litres. drain your bag back into to kettle, by suspending over it, or transfer it to a bucket, (keeping it raised off the bottom. I use to use an inverted colander.). As Donny, said, dont be afraid of a little squeeze. Mind your hands- them grains are hot. You can use a sauce pan lid or twist the bag. Whatever way, these drainings are important for your extraction efficiency. They are full of the good stuff.
4: guessing that you are familiar with your instruments, as you've done extracts, etc. But could you have made a mistake measuring out the grain bill. Ie not used enough? (i did a similar thing myself, but the other way round, in that i added too much grain and ended up with a higher gravity than expected). When you were taking the gravity reading, did you let the sample cool? It is a help to take a pre boil gravity reading also (as an exercise, you can take a sample before you add the bag drainings back in, and afterwards to see the effects.)  so you know if you have an issue, and can adjust the boil, or dilute if necessary and adjust hop additions according


Anyway, just some thoughts, that you probably have covered anyway.

[TheSumOfAllBeers]

A useful exercise when you are calculating efficiency is to work out the total "gravity points" at the various stages of the process.

E.g. If my grain bill has a maximum extract of 2800, and I end up with 50L of 1.040 wort, then I have 40x 50= 2000 gravity points of extract.

Express ed as a percentage ~ 71%

It gives you a predictor of what will happen during the boil if you measure B/O rate correctly.

The formula is a bit faffy if your s/w quotes you US units, but very doable

[banjobrew]

Thanks everyone. All great advice.

The strainer I had wasn't strong enough... I wasn't expecting the bag to be quite so heavy. This is why I didn't squeeze or suspend the bag for long enough. I've spied a good'un for the next brew.

I'll take as many gravity readings as I can next time.

I could really use a sight glass or a litre stick to get an accurate boil off rate and hit my desired boil volume.

I'll request a finer crush from the HBC next time too.

Sorry, just thinking out loud.

Thanks again!

[Donny]

The more you brew the better you will get at it. Every mistake you make improves your next brew. Ive made a good few brews now and only on the last one did I figure out that the volume markings on the side of my PECO boiler are incorrect. Lots can go wrong which in time will make you a better brewer.

Id be eons behind if it werent for this forum.