Does too much Caramalt = high FG?

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gmorosi

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Hi Guys and Gals,

Apologies if this question has been answered before, but I've been unable to find anything conclusive.

I did my first AG brew (BIAB) about 11 days ago, and it looks like fermentation might be finished now, however the FG looks to be pretty high (1.020).

I did a slight variation of a Dr Smurto's GA (Used Galaxy/Cascade instead of Amarillo) with the following grain bill:

JW Trad Ale x 2400g
Weyermann Munich I x 800g
JW Wheat Malt x 800g
Caramalt x 500g

The problem was that the HB store I ordered the grain from had a 500g minimum on grains (Hence the 500 of Caramalt) and I mistakingly said yes to them putting it into the one bag as I'd confused this order with another order I made at the same time. I spoke with the bloke from said HB store and he said it should be fine, just lower my mash temp by a degree or so to compensate.

Mash temps were about 66 degrees at the start, 65 after 30 mins, 64 after 1 hour (I turned the urn back on for a few minutes to bring back to 66) and then about 65 after the full 90 minutes.

Everything went fairly smoothly, but it appears that fermentation is either stuck - or has finished higher than expected. The gravity at the start was bang on expected @ 1.047 - however I've been measuring it morning and night over the last few days (Using fefractometer) and it appears static @ 1.020.

I used a rehydrated US-05 yeast, and temps have been pretty cool @ around 16-18c for the first week or so and have been creeping up to around 20c this week.

Is this something to be expected given the additional Caramalt?

I accidentally had a little too much trub in the fermenter, so to racked everything to a secondary last night and about 30 minutes after sealing everything up I seemed to have kick started fermentation again - however this morning when I checked it there was no airlock activity and another check on the refractometer showed a reading of 5 Brix (1.020/Same as the last 2 or 3 days). If anything it might have been ever so slightly under 5, but looked pretty much the same.

I'm happy to give it more time if it's likely to help - I really want to avoid angering the wife with bottle bombs off my first batch! Just not sure what effect the additional Caramalt will have.

Sorry again if this has been done to death!

Thanks in advance for any advice!
 
Caramalt shouldnt be your prob. I would say it has stalled.

What temp is the ferm at
 
Thanks for that.

Currently sitting at around 18 degrees. I don't have a fridge yet so it's a bit tricky to regulate, but for the most part it's been hovering between 16-18 degrees.
It certainly seemed to kick back into life after I racked it, but as of this morning it seemed pretty quiet
 
Give it a frw more days. It wont hurt it to let it sit in the ferm.
 
No worries - I wasn't planning to bottle until Sunday anyway, but was just concerned about bottling if it hadn't dropped any lower than 1.020
 
The issue is you need to apply a correction to your refractometer reading for alcohol as alcohol will skew the reading. There are many calculators on the net, search for "refractometer alcohol correction calculator", the one I use is here


edit: removed the low brix reading comment as I just calculated it out and 5 is ok
 
Thanks QldKev! I had no idea I had to take the alcohol into consideration!

Taking that into consideration, the 3 or 4 calculators I've punched my numbers into are all saying 1.006-1.009 (Which seems lower than my spreadsheet said I should have gotten) - but certainly makes me more comfortable than thinking I had 1.020!

Either way I'll check it with the hydrometer before bottling to be sure, but it looks like I'm good to go!

Thanks for the speedy responses guys!
 
By looking at it I though you were quite low, but I worked it out using Beersmith 1.010 to be expected FG, so you are pretty close and since it's been there for a few days you are good to go.
 
Kev has cottoned onto your problem. The 10% cara/crystal (dextrinous/less fermentable) malt in your recipe would not result in (100 * (1.047 – 1.020)/(1.047 – 1.0) ) = 57.44% apparent attenuation from S-05

Cheers,

Screwy
 

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