A problem with my maths - Mini-BIAB

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coloneldom

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G'day guys,

I'm having a little trouble with my calculations after completing my first All Grain mini-BIAB - I understand some of this may be pretty simple stuff, but I feel like I've gone wrong somewhere along the way. Anyway, here's my issue.

I put down Ross' Nelson Sauvin Summer Ale a few days ago, doing it as a mini BIAB so basically halved all the ingredients for a mini-BIAB

- 2.5kg Maris Oter Pale
- 0.25kg Flaked wheat
- 40g of Nelson Sauvin hops over 4 additions.

I was using a 24L aluminium stockpot I rustled up at a catering store, put everything through beersmith and a BIAB calculator. Per the maths, I put 19L of water into the pot with aim of putting approx 11.5L into the fermenter.

Mash went perfectly, mashed at 60c for 90 mins with only a couple of degrees temp loss. The pre boil OG was 1.028 @ 59c which adjusted for temp is 1.041

Unfortunately I had a lot of difficulty maintaining any sort of rolling boil and had to increase the "boil" time to 90mins rather than the initally planned 60. When I say I had trouble boiling I mean it basically sat at 96c for the whole time, never really hit any sort of boil at all. I adjusted my hop additions accordingly, other than the first lot through.

Post all this I put it into the fermenter today, only managing to get 8L, with an OG of 1.052.

AT this stage it tastes very sweet with a distinct chemical undertone, maybe an acetone type flavour?

My question for everyone is where have I stuffed up in my maths, how can I calculate my efficiency, and finally, have I ruined my brew at some stage? I've got enough of the same ingredients ready to go again so am pretty keen to give it another crack.

Thank you all in advance!
 
did this recipe for my first AG, albeit at a larger scale.
we used a camp stove to do the heating, it didnt quite have enough grunt to get a rolling boil, the surface was kinda just moving a little. had to have the lid half on.

in my experience, with this recipe, and worrying about it the whole way... let it do its thing.
for the first couple of weeks in the fermenter, it tasted rather sweet and just generally sh*t... but it did smell amazing.
but once it had been in the fermenter for 4 weeks.... boy did it change.

currently in the bottle for coming on 2 months, and its my best brew yet. was ready to drink in 2 weeks.
 
You realise a 60c mash is going to give you an extremely fermentable beer, right? Likely to have a higher alc content than intended, and be very crisp and 'thin'.

Wort tastes sweet because it is. That's normal.
 
Apologies, that was a typo, mash temp was 66c not 60c.

Does anyone think it's worth topping up the fermenter with water to increase the volume?
 
Only if you want to water it down. It'll be like 5ish %. When using beersmith you really need to take the time to set it up properly. Work backwards from you required amount in fermenter.

Put a lid half on to help get boil or put a bowl on top.
 
mine started at 1.060 (i got a very good mash) and ended up at 1.010... for 6.6% before priming
still tastes prety damn good... just not a session beer...
 
Not sure what your off flavours are. But the initial figures seem about right...except for your finishing volume.

I also do 10 litre batches. BIAB. I start with 17.5l, and get 10 litres into the glass fermentor leaving most of the trub behind. So even with your lack of significant boil, I have no idea where you're losing your volume.

How much are you letting your grains drain after lifting the bag?
Hop pellets?
How are you chilling?
 
Yeah that was my biggest concern, it was just chilled in a laundry sink over about a day. I used hop pellets dared straight to the boil. Could the extended 90 min "boil", despite it's lack of any significant boil, account for the extra loss?
 
The " extended " boil can be the only logical explanation for the low finished volume.
Ruling out the obvious , you allowed the bag to drain sufficiently and there were not leaks and or major spills.
Although as you said you had trouble getting a rolling boil the loss of volume will still happen,90 minutes @ near boiling will still result in loss.
Cheers....spog.....
 
Cheers everyone for the reply, so given that the extended boil is likely the biggest contributor for the volume loss I have an additional question for you.

If I was to continue to have the same issue with maintaining a rolling boil, should I extend the boil time (and adjust volumes accordingly) or simply stick with what recipes are calling for? Is the lack of a good boil an issue for flavours etc?
 
get a bigger burner :)

you could also invest in an 'over the side' element, just hangs in the wort and gives you that extra little bit of ooomph
 
Seems the ol' electric stove isn't cutting it at the moment. I do have a separate pot, so for the moment I guess I could split my wort, with hop additions in one? Until I upgrade anyway.

I guess this means my efficiency is pretty shot at the moment too? My calcs seem to suggest about 50% eff. Time to get practicing!! :)
 
Get a gas burner. Electric hot plates can be slow. A trick is to cover the surface area, just google "how to get a roiling boil on an electric stove" or put a lid half on pot. Eff will increase with time, but make sure your not reading the brewhouse eff from beersmith, which I believe you are. Go to the mash tab an input all your readings for mash eff.
 
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