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High FG issue

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bobtheUKbrewer2

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I brew SMASH beers and typical OG-FG values I obtain are

17.6,9 15.8,7.8 15,8 12.6,7.8 11.2,6.6 9.7,5 7,4 (BRIX)

Any ideas why FG is so high ? I mash at 69-71 deg C and bottle after 4 to 6 days. My brew volume is 13 litres and I use a sachet of Safale 04 for each brew. Thanks.
 

bracconiere

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I'm going to repeat what i've read here before, and ask if your using a refractometer for your FG, because apparently alcohol messes them up...so they only work for OG, you need to use a hydrometer, or some sorta calc for FG
 

Pappers_

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1) You're mashing at a high temperature, which will leave you with a less fermentable wort and a higher final gravity. In summary, 65C will yield a more dry beer with a light body, 67C will yield a balanced, medium body beer, and 69F will yield a sweeter, full bodied beer. That sentence lacks nuance, but you get my point.

2) Don't be in such a rush to bottle. Let the yeast do their business, give them a little more time, you might lose a point or two of gravity if you wait two or even three weeks to bottle.
 

kevin58

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Running just your first set of numbers and without knowing your correction factor your OG looks to be 1.072 and your FG is somewhere in the neighborhood of 1.015. Personally, I wouldn't find those to be out of line.

I would caution against bottling as early as you do. You may no longer see activity in your airlock after 4 to 6 days but that does not mean your yeast is finished doing its job. They are cleaning up other compounds and need time to finish before you package your beer.
 

myndflyte

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Here's Zymurgy's updated formula to convert Brix to gravity after fermentation:

FG = (-0.002349Bxi + 0.006276Bxf) + 1
ABW = 0.67062Bxi - 0.66091Bxf
ABV = (FG * ABW)/0.791

Bxi is brix initial and Bxf is brix final.

As others have said, refractometer readings after fermentation usually come out higher because of the alcohol.
 

Mark Buster

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and on a more serious note....

https://brucrafter.com/convert-brix-to-sg/

use the after ferm calc and you ended up on the 17.6->9 with a final gravity of 1.013 which sounds about right...

15.8->7.8 would be corrected to 1.010 which is fine...

if you want it drier than that, refer to my last post, :mug:
Hey, thanks for using my blog, glad you find it helpful!
 

bracconiere

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Hey, thanks for using my blog, glad you find it helpful!
I don't own a refractometer, actually. i've just seen this question asked like 4-5 times since i joined the forum, and knew the answer....lol...And your the first google result for a calc that had temp correction i got!
 
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bobtheUKbrewer2

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Kevin58 - some of my bottles are 2 litre PET so surely the yeasties will do their stuff in bottle ?
 

Andre3000

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As I recall, S04 is not a high attenuator, so the FG numbers look fine. It's more the OG numbers that are more puzzling. What's your process like and why did it change so much from the initial sets? Did you intend to hit such low OGs?

Sean Terrill has done some good work on creating a relatively accurate FG / refractometer calculator:

http://seanterrill.com/2012/01/06/refractometer-calculator/

I think it's probably the best one going.
 
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bracconiere

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As I recall, S04 is not a high attenuator, so the FG numbers look fine. It's more the OG numbers that are more puzzling. What's your process like and why did it change so much from the initial sets? Did you intend to hit such low OGs?

Sean Terrill has done some good work on creating a relatively accurate FG / refractometer calculator:

http://seanterrill.com/2012/01/06/refractometer-calculator/

I think it's probably the best one going.
i just assumed he got bored of writing both and trailed on about the FG's at the end?

maybe not though, but this would be a seriously BAD batch, an increase in Gravity! "6.6 9.7"

i wonder if that could be the narcan for getting drunk!
 

Andre3000

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i just assumed he got bored of writing both and trailed on about the FG's at the end?

maybe not though, but this would be a seriously BAD batch, an increase in Gravity! "6.6 9.7"

i wonder if that could be the narcan for getting drunk!
An increase in gravity means the yeast feel so bad for your brewing ability, they left you some sugar out of pity then got the hell outta Dodge :drunk:.

Seriously though, I just assumed 11.2,6.6 9.7,5 was:

OG 11.2
FG 6.6

OG 9.7
FG 5

but now you've got me second guessing myself!
 

bracconiere

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An increase in gravity means the yeast feel so bad for your brewing ability, they left you some sugar out of pity then got the hell outta Dodge :drunk:.

Seriously though, I just assumed 11.2,6.6 9.7,5 was:

OG 11.2
FG 6.6

OG 9.7
FG 5

but now you've got me second guessing myself!
new homebrewers joining the ranks all the time it's a good thing! we just gotta have a good time going through the motions!

i'd say this guy sounds cool though, with the 2 liter bottles! ghetto like me!

and i actually learned something new, i think...so a refractometer doesn't need to be corrected for heat? that's why people use them for a OG reading?

if so i might think about upgraded my brew day!

(edit: that's why i like it here, google here i come i need to learn about refractometers! i was just regurgitating what i've already heard other people say already)

Edit #2:read this article, still think their a waste and a hydrometer is the way to go!)
 
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RM-MN

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and i actually learned something new, i think...so a refractometer doesn't need to be corrected for heat? that's why people use them for a OG reading?
Almost right. Most refractometers have automatic temperature compensation (ATC) and since the amount of wort needed for a reading is quite small, the wort cools right on the refractometer and the reading is correct....except if you get one that doesn't correct like it should. I lucked out and mine gets about 2 drops of the boiling wort for the reading and gets it right. Not all do.
 

IslandLizard

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I lucked out and mine gets about 2 drops of the boiling wort for the reading and gets it right.
I was never getting reliable readings when putting a drop of hot wort directly from the boil kettle on the prism. Then it dawned on me, some of the hot water evaporates from the prism, hence increasing the gravity.

So I let it cool down first to around 100-120F before even attempting a refractometer reading. I stick the sampling pipet with the bulb down in a small glass with some ice water. A minute later (or less) it has cooled sufficiently. Readings are accurate and repeatable.
 

bracconiere

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I was never getting reliable readings when putting a drop of hot wort directly from the boil kettle on the prism. Then it dawned on me, some of the hot water evaporates from the prism, hence increasing the gravity.

So I let it cool down first to around 100-120F before even attempting a refractometer reading. I stick the sampling pipet with the bulb down in a small glass with some ice water. A minute later (or less) it has cooled sufficiently. Readings are accurate and repeatable.
thanks for the tip just in case i need it for these forums, or an actual refractometer! things are like $100 bucks aren't they?
 

IslandLizard

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thanks for the tip just in case i need it for these forums, or an actual refractometer! things are like $100 bucks aren't they?
$20-25 from Amazon or eBay. As long as it has ATC, which most do.
I sprang the extra $3 and bought a heavier weighing unit, I hate holding instruments that feel flimsy. :D
 

bracconiere

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$20-25 from Amazon or eBay. As long as it has ATC, which most do.
I sprang the extra $3 and bought a heavier weighing unit, I hate holding instruments that feel flimsy. :D
hmm, have to look into it...and i know the feeling of flimsy feeling things...i wanted to find a refilable lighter, because i always hate getting attached to a bic then having to throw it away...for the $10 a year i was spending on bic's i ended up spending $100 on a bunch of flimsy semi-disposables, my '94 zippo replacement insert...finally ended up with a butane thunderbird with pizzo light for my '94 zippo case...feels good, just wish it had a bigger fuel tank. :off:
 

RM-MN

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I was never getting reliable readings when putting a drop of hot wort directly from the boil kettle on the prism. Then it dawned on me, some of the hot water evaporates from the prism, hence increasing the gravity.
My refractometer has a flip down cover for the prism. Drop the wort on and flip the cover immediately and no more evaporation.

sorry, it said that maltose and beer don't refract the same as sugar water and needs to be converted to SG no matter what?
I bought a refractometer that has the specific gravity scale built in. It seems to be right on at preboil and matches my hydrometer reading when cool.
 

balrog

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I've had trouble w evaporation like @IslandLizard but if I stir with spoon and immediately pour over prism and flip down cover, wait ~30s, it is repeatably done.

The calc that is closest to what I see is this one (have to sign up for free acct to use) but it matches what I get and I always measure with "std" hydrometer, and with "limited-range" start and limited range finish hydrometers that are easier to read, and refractometer. Yeah, it's overkill. Welcome to my brain on the data drug. All other Sean Terrill/BrewersFriend/BeerSmith/Zymurgy calculators have larger RMS calculated FG that what I measure with Hydrometer.

But I always measure with hydrometer.
 

IslandLizard

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My refractometer has a flip down cover for the prism. Drop the wort on and flip the cover immediately and no more evaporation.
Most, if not all, have a flip down cover. I guess I could never get the cover on fast enough.
stir with spoon and immediately pour over prism and flip down cover
That sounds messy, but you use a much larger amount of liquid, so any evaporation has much less impact.
I literally use 1 or 2 drops from the sample pipet. So any evaporation before the cover gets on makes a big difference.

I rely on the refractometer during the mash, boil and for the chilled wort in the fermenter. I use Sean Terrill's conversion formula once alcohol is present to get indications of where the gravity is, nothing critical, like the about-halfway attenuation point for the first dry hop in a NEIPA. Then for gravity change toward the end.

I get a hydrometer reading from the chilled wort going into the fermenter, for accuracy and ultimate reference, which always concurs with the refractometer within 1 or 2 points. Then whenever I siphon out a larger sample during fermentation, usually when it's finishing up, using a piece of skinny tubing snaked through the airlock hole.
The calc that is closest to what I see is this one (have to sign up for free acct to use) but it matches what I get and I always measure with "std" hydrometer
I'll check that link out. I've had the same experiences using various correction formulas, they never seem to match my hydrometer, even when tweaking the wort correction factor. Readings within 2 points is close enough for me. Besides, there's not much we can change about them.
 
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augiedoggy

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$20-25 from Amazon or eBay. As long as it has ATC, which most do.
I sprang the extra $3 and bought a heavier weighing unit, I hate holding instruments that feel flimsy. :D
I paid like $16 for both mine.. They are almost identical to the ones my local brewing store and my brewing partner has short of a different pattern in the rubber eye ring.
 
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