SG 1.078 down to FG 1.000? Infection or super-yeast? (Wyeast 3787)

[jesseb]

So a few weeks ago a brewed a Belgian double/quad coming in at a SG of 1.078. I've just bottled it and the refractometer gave an FG of 1.000. Wait what? Probably a wrong measurement. Measured again, still 1.000. The recipe had a hefty chunk of candy sugar in it, and I mashed deliberately on the lower end so the beer would turn out on a bit drier (relative to the high SG). The yeast used was top cropped of a blond beer I've brewed a few days earlier. (In high sight I've probably overpitch big time.) The fermentation took off after a few hours and went total bonkers within 12 hours or so. After a day or two it slowed down and I started ramping up the temp to 23C (73F).

The fermentation seemed normal. A thick krauzen formed and it smelled ok (well pretty bad actually, like sulfury farts, but this is normal for this yeast. I brewed with this yeast before and I did recognize the smell).
On the bottom of the primary sat the recognizable beige slurry, nothing out of the ordinary. I did transfer it to a secondary, perhaps caught some infection there? The final beer seems fine, just a lot of alcohol on the nose.

I guess my question is if this is possible for a yeast to achieve or does this hint to an infection? The given conditions where perhaps perfect for the yeast, but still, there is always some unfermentable residual sugar left, right? I know one of the characters of this yeast is a high attenuation, but even this high?

 

[Sammy86]

Something is definitely off...whether it was the SG or the FG...100% attenuation isn't a normal occurrence.

Even with the candy sugar in there there had to be some long-strains that couldn't be fermented.

I'm interested to see what the group has to say.

 

[day_trippr]

Well...3787 is rated for high 70s attenuation with decent alcohol tolerance, but finishing that low is suspicious.

I have a refectory ale in my repertoire that uses 3787, with an OG of 1.060 with a couple of pounds of light home made candi sugar that finishes around 1.012. So pretty much spot on wrt attenuation...

Cheers!

 

[jddevinn]

refractometer gave an FG

Can't use a refractometer directly for FG. You can use a calculator but need the wort factor that is specific to the beer.

 

[tripeland]

So a few weeks ago a brewed a Belgian double/quad coming in at a SG of 1.078. I've just bottled it and the refractometer gave an FG of 1.000. Wait what? Probably a wrong measurement. Measured again, still 1.000. The recipe had a hefty chunk of candy sugar in it, and I mashed deliberately on the lower end so the beer would turn out on a bit drier (relative to the high SG). The yeast used was top cropped of a blond beer I've brewed a few days earlier. (In high sight I've probably overpitch big time.) The fermentation took off after a few hours and went total bonkers within 12 hours or so. After a day or two it slowed down and I started ramping up the temp to 23C (73F).

The fermentation seemed normal. A thick krauzen formed and it smelled ok (well pretty bad actually, like sulfury farts, but this is normal for this yeast. I brewed with this yeast before and I did recognize the smell).
On the bottom of the primary sat the recognizable beige slurry, nothing out of the ordinary. I did transfer it to a secondary, perhaps caught some infection there? The final beer seems fine, just a lot of alcohol on the nose.

I guess my question is if this is possible for a yeast to achieve or does this hint to an infection? The given conditions where perhaps perfect for the yeast, but still, there is always some unfermentable residual sugar left, right? I know one of the characters of this yeast is a high attenuation, but even this high?

Use hydrometer for FG measurement. A refractometer will give an incorrect reading due to the presence of ethanol and the correction equations will not be 100% accurate. I assume your FG will still be low, maybe 1.004 to 1.008 or so.

 

[BrewZer]

So a few weeks ago a brewed a Belgian double/quad coming in at a SG of 1.078. I've just bottled it and the refractometer gave an FG of 1.000. Wait what? Probably a wrong measurement. Measured again, still 1.000. The recipe had a hefty chunk of candy sugar in it, and I mashed deliberately on the lower end so the beer would turn out on a bit drier (relative to the high SG). The yeast used was top cropped of a blond beer I've brewed a few days earlier. (In high sight I've probably overpitch big time.) The fermentation took off after a few hours and went total bonkers within 12 hours or so. After a day or two it slowed down and I started ramping up the temp to 23C (73F).

The fermentation seemed normal. A thick krauzen formed and it smelled ok (well pretty bad actually, like sulfury farts, but this is normal for this yeast. I brewed with this yeast before and I did recognize the smell).
On the bottom of the primary sat the recognizable beige slurry, nothing out of the ordinary. I did transfer it to a secondary, perhaps caught some infection there? The final beer seems fine, just a lot of alcohol on the nose.

I guess my question is if this is possible for a yeast to achieve or does this hint to an infection? The given conditions where perhaps perfect for the yeast, but still, there is always some unfermentable residual sugar left, right? I know one of the characters of this yeast is a high attenuation, but even this high?

Checking my logs... my sole experience with 3787 was a Trippel starting at 1.128 OG that fermented out to 1.016. The beer was memorable and my family considered it the best I've ever made. It was certainly the most expensive.

I believe the phrase you're looking for is "Don't Worry -- Have A Homebrew."

 

[Vale71]

Use hydrometer for FG measurement. A refractometer will give an incorrect reading due to the presence of ethanol and the correction equations will not be 100% accurate. I assume your FG will still be low, maybe 1.004 to 1.008 or so.

In the presence of alcohol a refractometer would give a higher than actual reading, so his reading of 1.000 would be even lower when corrected which is hard to believe. I think it's safe to assume he has applied the correction even though he did not say so explicitly.

To the OP: how "sizable" was that chunk of candi sugar? Are we talking like 30+% percent or just 10%?

 

[tripeland]

In the presence of alcohol a refractometer would give a higher than actual reading, so his reading of 1.000 would be even lower when corrected which is hard to believe. I think it's safe to assume he has applied the correction even though he did not say so explicitly.

To the OP: how "sizable" was that chunk of candi sugar? Are we talking like 30+% percent or just 10%?

Yes the measurement would be after correction, be it a few points out due to inaccuracy (1.000 vs more realistic 1.004). This is all assumption anyway. Key takeaway is to measure FG with hydrometer.

 

[jesseb]

Can't use a refractometer directly for FG. You can use a calculator but need the wort factor that is specific to the beer.

In the presence of alcohol a refractometer would give a higher than actual reading, so his reading of 1.000 would be even lower when corrected which is hard to believe. I think it's safe to assume he has applied the correction even though he did not say so explicitly.

To the OP: how "sizable" was that chunk of candi sugar? Are we talking like 30+% percent or just 10%?

Indeed I did the correction. The refractometer red 6.7 brix. Using the calculator on brewersfriend, the SG and the correction factor of 0.95 for this refr. I came on 1.000. The sugar was about 14% if I remember correctly. 8% dark candy and 6% table sugar.

Key takeaway is to measure FG with hydrometer.

Couldn't agree more. Usually, I only use a hydrometer for measurements but those damn things keep on breaking. Due to the shops being closed, I'm depending on a refractometer for now.

It could definitely be wrong measurements from either the SG or FG, or both. As said above, I used a refractometer for all the steps of the brewing process and to be honest, I do not trust those things to be accurate.

What about overpitching? Let's assume I pitched ten times the necessary amount of yeast, does this has an affect on attenuation?

 

[jesseb]

Checking my logs... my sole experience with 3787 was a Trippel starting at 1.128 OG that fermented out to 1.016. The beer was memorable and my family considered it the best I've ever made. It was certainly the most expensive.

I believe the phrase you're looking for is "Don't Worry -- Have A Homebrew."

Sounds like a heavy tripel! Considered calling it a barleywine? Perhaps a bit too dry for barleywine, though.

 

[Beenym88]

I never made this style before but one time I used a pound of honey and the fermentation overshot it’s FG like crazy. The yeast handle different sugars differently.

 

[Vale71]

Indeed I did the correction. The refractometer red 6.7 brix. Using the calculator on brewersfriend, the SG and the correction factor of 0.95 for this refr. I came on 1.000. The sugar was about 14% if I remember correctly. 8% dark candy and 6% table sugar.



Couldn't agree more. Usually, I only use a hydrometer for measurements but those damn things keep on breaking. Due to the shops being closed, I'm depending on a refractometer for now.

It could definitely be wrong measurements from either the SG or FG, or both. As said above, I used a refractometer for all the steps of the brewing process and to be honest, I do not trust those things to be accurate.

What about overpitching? Let's assume I pitched ten times the necessary amount of yeast, does this has an affect on attenuation?

No matter how much you overpitch Saccharomyces won't be able to ferment anything beyond maltotriose. 100% apparent attenuation is still way too high even with 14% refined sugars, either your measurements are wrong or your beer is infected. Since there are no apparent signs of an infection I would lean towards the former.

 

[hottpeper13]

I use a similar yeast from The Yeast Bay called Belgian Dry. They state it achieves 83-100% ADF. Check out if the 3787 is a diastaicus yeast. I believe 3787 has the STA-1 gene.

 

[Qhrumphf]

Wyeast doesn't list 3787 as STA1+, and in my experience it hasn't behaved as such. I too have often gotten high attenuation when mashing low and using sugar, but never THAT high.

It's possible that there's an infection with phenols being obscured by the 3787 phenols (though for it to work so quickly I'd expect it to be pretty apparent). Bad readings makes more sense.

 

[MikeCo]

The last Tripel I made with 3787 had all pilsner malt with 16% cane sugar. The OG was 1.074 and it finished at 1.006. With a combination of a few points of measurement error from you refractometer and subsequent error in the calculator, your actual FG could easily be a few points higher than the resulting 1.000.

 

[jesseb]

No matter how much you overpitch Saccharomyces won't be able to ferment anything beyond maltotriose. 100% apparent attenuation is still way too high even with 14% refined sugars, either your measurements are wrong or your beer is infected. Since there are no apparent signs of an infection I would lean towards the former.

The last Tripel I made with 3787 had all pilsner malt with 16% cane sugar. The OG was 1.074 and it finished at 1.006. With a combination of a few points of measurement error from you refractometer and subsequent error in the calculator, your actual FG could easily be a few points higher than the resulting 1.000.

Hopefully it is indeed an error. I'm going to let it carbonate and age for a while and taste if it has any off flavours.

Any benefit in measuring it again, after the added priming sugar?

 

[Oldskewl]

Have you brewed any Saisons lately? I love 3711 in my Saisons but every time I ferment with it, the beers following it end up over attenuated. No matter how well I clean. Only solution has been to use a very mild bleach/water solution to clean the fermenter and lines or replace them. It is the STA-1 gene mentioned earlier in the thread that is hard to get rid of.

 

[Nagorg]

I assume that your refractometer has also been calibrated with DI? Should be 1.00 when measuring DI. If its an accurate brix measurement, yeah that is low enough to believe that something isn't right.

FWIW, I do know the controversy over using a refractometer for FG. But as "they say", your milage may vary. I stopped using a hydrometer after doing my own testing using both methods as a comparison with several different batches. In all cases, I found the calculated FG via brix conversion to be right inline with by hydrometer measurements. If there was a difference, I couldn't tell it with my hydrometer...