First BIAB AG attempt - partial success?

[Yuz]

Hey Brewers,
Surely this has been done to death before but for the life of me I cannot work out the projected vs measured SG.
So, 5kg Red X (similar potency of a generic Ale malt 1.036), shoved in an urn @ 71C & 25L and removed 75mins later at 65C. The grain bag is then "cold sparged" - ie rinsed through a large colander, giving back about 6L wort back into the urn; Brought to rapid boil.
I had to top up with about 3L of boiling water through boil to get 21L cubing volume as the wort boiled (65min).
After boil I measured SG @ 1.036, whereas predicted it's meant to be 1.050? Refractometer is calibrated to 0.0 @ 20C.
Grains were crushed @ 1mm gap (couldn't go smaller as the rollers wouldn't grab them), so quite fine.
Where did I stuff up?

 

[brewermp]

Hey Yuz,

Welcome . Did you measure your pre boil gravity? Looking at the temp you did a single step mash at 71c?

You skipped an important temperature.

I personally do
~60 mins at ~64c
Then ~15 mins at 72c (very generic but a good starting point)

Ps don’t chuck your beer. Run it through and note down everything about the taste etc so that you learn from the brew

 

[Yuz]

Hey MP,
I'm too suspecting the temp was too high through the mash for this malt to lose 15 odd SG points;
As for temp rise towards the end - that'll be the next batch, considering this is only a 30L urn, I have to manipulate the wort to get as much density as possible into the cube and this is my first AG try...
We'll see, part of the process I guess
PS - NO WAY I'm chucking this brew, she smells delicious and is going into fermentasaurus tomorrow on a hungry cake of US-05

 

[mongey]

I stared ag a few months ago. Just put my 8th batch in the cube. Just keep brewing. Like anything a big part of the process is understanding your gear. The numbers will work allot better when you have all your water volumes and losses dialed in. Every set up is different. I’d say it took me 6 batches to really dial it in.

Working out consistently how much you are going to loose to trub is important. If using brew software I find it way more user friendly to use the kettle setting rather than fermenter a sit takes the loss into account

How did you work out your expected OG ?what was your expected efficiency ?

with my set up getting 21l in the cube ,means 26l in the kettle post boil ,5l trub loss. to get 1050 with 5kg standard ale malt I'd need like 85% efficiency . possible I have hit low 80's a couple times , but def high to shoot for every time ,especially on your first brew

 

[Yuz]

How did you work out your expected OG ?what was your expected efficiency ?

Going by Ian's BIAB calculator and other sources the SG should be @ 1.050 at these specs and efficiency @ 70%. From what I understand, my efficiency with this batch was like 50%...
I'll make another batch soon but I want to make an "sparge rinser" add - on (maybe a 20L vessel with bottom drilled out sitting on top of the Urn), so I can "hot sparge" the BIAB bag @ 75C.
This will also allow for larger initial boil volume - I'm hoping for 26L or so - this way I won't need to add water. Similar to WEAL's recent post re: custom made hood for the Guten.
We'll see

 

[mongey]

Going by Ian's BIAB calculator and other sources the SG should be @ 1.050 at these specs and efficiency @ 70%. From what I understand, my efficiency with this batch was like 50%...
I'll make another batch soon but I want to make an "sparge rinser" add - on (maybe a 20L vessel with bottom drilled out sitting on top of the Urn), so I can "hot sparge" the BIAB bag @ 75C.
This will also allow for larger initial boil volume - I'm hoping for 26L or so - this way I won't need to add water. Similar to WEAL's recent post re: custom made hood for the Guten.
We'll see

how much did you have in the kettle before cubing ? how much left over trub did you chuck away ?

fermenter volume doesn't account for that .it only accurate if every drop from the kettle goes into the fermenter

 

[shacked]

When I did brew-in-a-bag, I couldn't get efficiency above 60% with it dropping as low as 45% for high gravity beers. With my 80L 4V system, I get 65% on 1.05 - 1.060, a bit higher on smaller beers and a big lower on big beers. Don't get to caught up on the number and focus on consistency. Keep a bag of DME or cane sugar around and top up with that if you fall a bit short (for hop utilisation mostly).

Here's what I'd do:

• Do a mash out at the end of your main mash (raise to 75-78C). This will impact viscosity and help your lautering.
• Sparge in a bucket. Fill a bucket with your hot sparge water and leave your basket in there for 10 mins or so, then separate and add to your boil.
• Check your boil off rate. Some of the cheaper elements don't get much boil off so this may be impacting your numbers.
• Start with an assumption of 50% and go from there. Grain is cheap! Just add another kg or so.

 

[mongey]

well I just went down a rabbit hole of threads about whether its better to use brew house or kettle ending numbers . kettle def makes more sense in my simple brain and seems to be a more consistent language between different set ups . looking at recipes online I think people often quote brew house when they mean kettle at times .anyway that's a different conversation

as Shacked said all that matters is you are consistent and can predict what you are making. I know 5kg of grain will get me 22 l of beer around 5% into my fermenter and go from there . doesn't really matter what number that equates to

 

[Yuz]

I'll stick with the same grain and same amount and vary the process a little to figure it out. Mainly mashing temp (next batch will aim @ 65C) & "proper" sparge @70C, without any plain water additions.