Streak of bad luck with reaching FG, can this beer be salvaged?

[fasttimes]

I'm having a heck of a time lately with my last 3 beers getting to my FG and I'm trying to find out the source of the issue. I've recently switched to using dry yeast, and also have been doubling up on yeast packets. I add O2 to the wort with an O2 can and stone. Usually letting it run for about a min. I get fermentation starting, but they seem to slow and stop sooner than they should. The only suspect I have is the O2 process. I never know if the can is sending enough gas into the wort. Can't tell if it's getting near empty either. Perhaps the O2 can is low and not pushing out enough gas for the amount of yeast?

My latest batch is an extract Sweet Stout. OG was 1.056 and now 12 days later I'm only at 1.035. Two packs for Nottingham Ale 11g was used. Two days ago I raised the temp up to 75 to see if I can get a response from the yeast, but so far nothing.

Any suggestions on saving this batch? Should I add another pack of yeast? Add more O2? Add yeast nutrients? 2.7% ABV beer is not what I had in mind.

 

[stpug]

If you happen to be using a refractometer for your gravity readings then perhaps you're not correcting for alcohol. You can use refractometer calculators to help you adjust for alcohol.

If you're using a hydrometer then the situation is different.

 

[SiriusStarr]

Stupid question, but are you rehydrating your yeast? I can't imagine it would make that big of a difference, but it would certainly negatively impact yeast health if you're not.

 

[fasttimes]

I am using a refractometer for my readings. I wasn't aware I needed to correct them. I just assumed they are reading the beer's alcohol based on amount of light passing through.

I do re-hydrate the yeast prior to adding to the wort.

 

[SiriusStarr]

I am using a refractometer for my readings. I wasn't aware I needed to correct them. I just assumed they are reading the beer's alcohol based on amount of light passing through.

I do re-hydrate the yeast prior to adding to the wort.

Ah, no. Refractometers measure (perhaps not surprisingly) the refractive index of the sample, which varies (approximately) linearly with the amount of dissolved solids in solution. Since ethanol's refractive index is different from water, the ethanol in solution will skew this reading and needs to be compensated for. Hydrometers are really the only way to tell accurately what the F.G. of your beer is, though refractometers can tell you when the reading is stable.

 

[stpug]

I get very reliable results using a refractometer for both OG and FG readings using the Beersmith refractometer tool. So far, I've compared about 10 beers using corrected refract gravities with hydro gravities. I am generally within one point difference, and that's totally within my margin of error on reading the hydrometer. Granted, your equipment will make a difference. I only use the Brix % reading since my refract is Brix only (no dual scale). Dual-scale refractometers have been known to provide unacceptable SG conversions, so I would recommend only using the Brix% readings.

Edit: The only other calculator I've tried is Sean Terrells calculator and I find it to be much less reliable than BeerSmiths.

Edit2: Running a couple of my examples through onebeer's tool indicates that it also has a larger margin of error than BeerSmiths for my equipment. For the couple example I ran, I'm seeing about an additional 0.5-1 point difference (i.e. +/- 2 points) which is actually slightly better than Sean Terrells calculator on my equipment.

 

[archer75]

This is the site I use to handle corrections.

When first using a refractometer I still used my hydrometer for awhile just to ensure it was accurate. So far it's been 100% dead on. Both the OG and the corrections from that site.

 

[SiriusStarr]

From what I've heard, if you find the corrections that work for your equipment, they're pretty consistent, but you'd do best to check at least the first couple of times. I've yet to try with mine, but it sounds like others have had success.

 

[austinb]

Have you double checked the accuracy of your thermometer? I had similar issues brewing all grain with a bad thermometer and too hot a mash but that doesn't explain your extract batch. But if the thermometer was off perhaps you pitched the yeast while the wort was too hot or your ferm temp is lower than you thought.

 

[fasttimes]

I guess I should verify that my thermometers are working correctly. As for this batch of Sweet Stout, should I bother adding another packet of yeast to it and try to save the batch?

 

[LLBeanJ]

No. You don't have an FG problem with your beer.

I am using a refractometer for my readings. I wasn't aware I needed to correct them. I just assumed they are reading the beer's alcohol based on amount of light passing through.

This ^^^ is your problem. Your FG readings from your refractometer are inaccurate. Either run your readings through one of the various correction formulas out there or take a hydrometer reading and you'll find that to be the case. Do one or the other (or both) and report back your findings.

 

[archer75]

What is your og and what is your current brix?

 

[fasttimes]

Just tested with my hydrometer and after temp correction I'm only at 1.034, 1.032 before temp correction. My OG was 1.056.

 

[archer75]

What's the brix on your refractometer say?

 

[jfolks]

wait...you have a refractometer for extract brews?! that's like having a steering wheel from a porsche in your pinto. I'm just kiddin ya know..but I must admit I'm surprised.

Obviously, this isn't your issue..but...I was talking to the head brewer at Gigantic and he said that refractometers do not effectively evaluate gravity once alcohol is present- he said they just use a hydrometer for FG. I cant speak to beersmith adjustments, but apparently hydrometers are the way to go for FG

 

[MindenMan]

Even though it doesn't make sense to me, but it works, add white sugar and the yeasties will get busy again, lowering your F.G. I didn't see anyone ask, or I missed it, are you AG or extract? Extract brews have a habit of not wanting to go below 1.020. IDKJAT