Perputually missing FG

[Spookism]

Hi guys,

6 brews in with my GrainFather and everything is going smoothly up until the end.
The FG on all my brews has been way over, making my beer a good 2% under what BeerSmith says it should be with ABV.
I've gone from just dropping dry yeast in to re-hydrating the yeast.
I've got a temp controlled fridge which is at 20 degrees all fermentation.
And I always pretty much nail the OG, which makes this all the more confusing.
I can under stand one or two, but I'm half a dozen in and I've improved my techniques yet this is still happening?

Any thoughts?

 

[Rocker1986]

Mash temperature? Grains used? Yeast used?

Are you measuring FG with a refractometer and not adjusting it for alcohol being present?

 

[Spookism]

I should add that my current brews in fermentation are

Golden Ale
OG: 1.053
Est FG: 1.011
Current FG 1.026

Days in fermenter: 14

Summer Ale
OG: 1.045
Est FG: 1.013
Current FG: 1.029

Days in fermenter: 10

 

[Spookism]

Mash temperature? Grains used? Yeast used?

Are you measuring FG with a refractometer and not adjusting it for alcohol being present?

67 degrees

Maris Otter/Torriefied - us-05

Pilsner/Wheat Malt/Munich II/Cara II - bry-97


I am using a refractometer - I may be using that incorrect, but the OG was always good.

 

[mikeybycrikey]

There's ya problem. Once alcohol is involved you need to do some calcs to get a refractometer to read right. Beersmith mobile has a handy tool that does it.

 

[sponge]

^^ What he said.

EDIT: If you've got a hydrometer, you can compare to the corrected refractometer reading.

 

[Coodgee]

They need to put a bloody warning label on refractometers. This catches out so many people including me. Your corrected fgs are 1012 and 1016 for the beers above.

Using the excellent tool on the grain father site

http://www.grainfather.com.au/#!brewing-calculator/cljs

 

[Spookism]

There's ya problem. Once alcohol is involved you need to do some calcs to get a refractometer to read right. Beersmith mobile has a handy tool that does it.

^^ What he said.

EDIT: If you've got a hydrometer, you can compare to the corrected refractometer reading.

Thanks guys, I will look into this as soon as I can (at work) and will let you know.

If true, it would make sense as to why I was getting drunk of what I thought were mid strength....

 

[Spookism]

They need to put a bloody warning pushrod on refractometers. This catches out so many people including me. Your corrected fgs are 1012 and 1016 for the beers above.

Using the excellent tool on the grain father site

http://www.grainfather.com.au/#!brewing-calculator/cljs

Awesome, which means they're pretty much spot on.


Thanks again everyone, I'm not as bad as what I thought.

 

[danestead]

Hahaha, sorry I have to laugh. But on a serious note, I too bought a refractometer a few years ago thinking they are the ducks nuts, but they aren't really. They really just confuse things at times. They are very good at doing certain things though.

 

[Danscraftbeer]

All is well then that's awesome. All you need is a hydrometer as mentioned. I wouldn't bother with calculations of refractometer post ferment. Its only good for pre ferment readings and you only need a drop. Comparing it with hydrometer confirms that's its correct. Besides you need that 70ml for a hydrometer test for post fermented beer to also smell and taste test.

 

[Spookism]

Thanks again guys.
Such a damn rookie. But it's also a good feeling learning something new everytime, meaning my next brew is going to be even better.

 

[mr_wibble]

In case someone else is reading this, one other thing to check for low FG is the oxygenation of the wort.

And FWIW every couple of months I forget and use the refractometer for final gravity too: 1025! WTF!!! ... Ah refractometer.

 

[antiphile]

As per usual, it seems I'm the odd one out. Just love the refractometer and wouldn't be without one now. Pour about 30 ml thru the tap into a shot glass, put a few drops on the meter, reading into the spreadsheet and there you go.

Give the rest a whiff and a taste, and it's all done. It really comes into it's own when there's a few brews to be checked 'cos it's so quick.

Every 4 to 6 weeks it needs to be recalibrated, but after the first few times it's needed very little or no adjustment at all. But I'll admit I do a hydro comparison at OG and FG to be sure.