Help! My first BIAB All-Grain has landed me with low OG

[RxAngus]

Hi all,

Tried my first BIAB today using Klarstein Fullhorn. I've ended up with low OG and (possibly) volume and would welcome any advice on where I've gone wrong. I saw another thread similar but thought it best to start afresh!

The recipe was a BrewUK all grain kit for Landlord. Total grains were 4.28Kg and I mashed at 66'C lid on for the stated 90mins using 10.7L of water I'd heated to 73'C. Made sure I'd got as much as I could from the bag by gently squeeze. During the mash I stirred a good few times and drew off and recirculated some wort maybe three times.

Topped up to just shy of 26L pre boil then boiled lid off for 90mins again as per recipe. Now here's the thing - Final volume was just over 19L and OG in the fermenter before pitching was 1034 instead of the recipe's 1042.

Now I did some testing of the Fullhorn with water previously and the boil losses were around 2L/hour. I seem to have lost 6+ litres today over 90mins. Is that possible due to grain and hop absorption? As I say, grains were pretty well drained.

Any suggestions very welcome on both the volume and OG issues.

Thanks

 

[Horners]

Hi all,

Tried my first BIAB today using Klarstein Fullhorn. I've ended up with low OG and (possibly) volume and would welcome any advice on where I've gone wrong. I saw another thread similar but thought it best to start afresh!

The recipe was a BrewUK all grain kit for Landlord. Total grains were 4.28Kg and I mashed at 66'C lid on for the stated 90mins using 10.7L of water I'd heated to 73'C. Made sure I'd got as much as I could from the bag by gently squeeze. During the mash I stirred a good few times and drew off and recirculated some wort maybe three times.

Topped up to just shy of 26L pre boil then boiled lid off for 90mins again as per recipe. Now here's the thing - Final volume was just over 19L and OG in the fermenter before pitching was 1034 instead of the recipe's 1042.

Now I did some testing of the Fullhorn with water previously and the boil losses were around 2L/hour. I seem to have lost 6+ litres today over 90mins. Is that possible due to grain and hop absorption? As I say, grains were pretty well drained.

Any suggestions very welcome on both the volume and OG issues.

Thanks

Did you cool wort to 20c before taking gravity reading?

 

[RxAngus]

Did you cool wort to 20c before taking gravity reading?

It was about 24'C when I took the reading which I understand would make a difference but not as much as I saw.

I should have said in original post that all temperatures were measured with a digital thermometer ie I didn't just rely on the Fullhorn display.

 

[MmmBeer]

My first thought on this is that 10.7 litres mash water doesn't sound like enough. I am not familiar with the Fullhorn, but the pictures I found suggest that there is a false bottom and therefore some dead space beneath it. I am assuming 10.7 litres was specified by the kit makers, which for this grain bill equates to 2.5 litres/kg, which is kinda ok, if a little on the dry side, but if there is dead space of say 2 litres below the false bottom, this drops to 2.0 litres/kg.

When you say that you 'topped off to just shy of 26 l pre boil', does that mean that you added fresh water into the boiler or did you dunk sparge the grain bag? I remember some years ago staying in a B&B in Dufftown, (run by an ex cooper's wife) whilst working locally. After finishing the project we had time to tour the Glenfiddich distillery, where the tour guide took great pride in the Scottish stereotype of frugality, explaining that after mashing, there were still a lot of sugars left on the grains, so they soaked them again in fresh hot water to rinse out as much as possible.

I make 23 l batches in a Grainfather and usually rely on the software to calculate mash and sparge volumes, but I find that I need about 31 litres in total to end up with 23 litres in the FV. Yours may be different, but use todays results to calculate mash and sparge water volumes for future brews.

 

[RxAngus]

My first thought on this is that 10.7 litres mash water doesn't sound like enough. I am not familiar with the Fullhorn, but the pictures I found suggest that there is a false bottom and therefore some dead space beneath it. I am assuming 10.7 litres was specified by the kit makers, which for this grain bill equates to 2.5 litres/kg, which is kinda ok, if a little on the dry side, but if there is dead space of say 2 litres below the false bottom, this drops to 2.0 litres/kg.

When you say that you 'topped off to just shy of 26 l pre boil', does that mean that you added fresh water into the boiler or did you dunk sparge the grain bag? I remember some years ago staying in a B&B in Dufftown, (run by an ex cooper's wife) whilst working locally. After finishing the project we had time to tour the Glenfiddich distillery, where the tour guide took great pride in the Scottish stereotype of frugality, explaining that after mashing, there were still a lot of sugars left on the grains, so they soaked them again in fresh hot water to rinse out as much as possible.

I make 23 l batches in a Grainfather and usually rely on the software to calculate mash and sparge volumes, but I find that I need about 31 litres in total to end up with 23 litres in the FV. Yours may be different, but use todays results to calculate mash and sparge water volumes for future brews.

Many thanks. The Fullhorn has 1L of deadspace below the valve and of course probably a bit more above it but below the false bottom. Looks like I've not used enough water in the mash then?

I added hot water to the boiler but didn't dunk sparge the bag because I'd read that was not really necessary with BIAB. I did drain it into the fermenting bin though and reintroduce what came out into the boiler. Maybe I need to dunk sparge in reality?

I'll use all of today's experience for the future so nothing's been lost really - just wanted to check I was doing nothing fundamentally wrong.

Yes I am living in an area where I should understand mashing very well. Been round Glenfiddich so many times I could give the tour!

 

[smcc]

too thick mash can mean water is not properly in contact with the full grain load, this is execerbated if you dont have flow via a pump. I would say though not sparging is probably your main issue, with grain once you pull out the bag and let it drain residual sugar will still cling to the grain its why every single professional brewery will sparge you probably left a fair few points behind

 

[RxAngus]

too thick mash can mean water is not properly in contact with the full grain load, this is execerbated if you dont have flow via a pump. I would say though not sparging is probably your main issue, with grain once you pull out the bag and let it drain residual sugar will still cling to the grain its why every single professional brewery will sparge you probably left a fair few points behind

Thanks, will definitely do some sort of sparge next time and an iodine test too.