HIGH FG/Fermentation stopped

[paanderson86]

Hey all. I have a problem. The gravity of my stout after two weeks is at 1.040. I checked it initially after 10 days and this was the case then so I moved it (was at 62 deg and is now 66 deg) and agitated the yeast to get it going again, but this obviously did not work.

Some points about my beer:
- My stout has no unfermentables
- The OG was 1.072
- I used S-04 for dry yeast, one pack. I know this will be a sticky point, but I’ve never used more than one pack and have never had any troubles with high FG or off tastes for that matter
- This was an all grain brew, and I used some of the sparge sort to hydrate the yeast at 80-90 deg, as indicated. This got the yeast rolling, as it always does

Any thoughts on where I went wrong, and more importantly how I can get the beer going now?

Thanks everyone.

 

[paanderson86]

Also, mash temp started at 155 and was at 147 after a few hours.

 

[Yooper]

You say you have no unfermentables, but apparently there are some in there or the FG would be lower. Mashing at 155 would favor a less fermentable wort with more unfermentable sugars.

You could try another yeast pitch, but I'm thinking that the stout is done.

 

[paanderson86]

I had candi syrup in it but that is fermentable, no?

 

[paanderson86]

And do you think that starting at 155 would really make it stop at 1.040? I’ve only done two all grain brews now but that seems really high

 

[Yooper]

And do you think that starting at 155 would really make it stop at 1.040? I’ve only done two all grain brews now but that seems really high

Yes, a high mash temperature would favor a higher FG. Candi syrup is fermentable, but the darker candi syrup is a bit less so. A high mash temperature means conversion would happen fast, usually within 15-20 minutes, and so you probably have quite a bit of more complex sugars. If you look at the recipe, darker crystals are less fermentable than, say, base malt, plus with the high mash temperature you'd be really favoring that high FG.

 

[paanderson86]

What is the preferred temp? I was trying for 154 because I knew it would drop some (crappy cooler). Calculations say that FG should be 1.022. I can’t imagine that one degree off would cause an 18-point change, would it? I’m just still kinda new to this and don’t know how easily things can be swayed. Thanks for your help.

 

[paanderson86]

10 lb of Golden Promise for the base malt, for what that’s worth.

 

[seatazzz]

How are you checking your gravity, a hydrometer or refractometer? If you are using a hydrometer (and you should be with alcohol present) may want to check it against distilled water, and adjust if necessary.

S04 is notorious for slow fermentations. Might just need some more time, but in my opinion (unless your hydrometer needs to be calibrated) you underpitched.

 

[paanderson86]

How are you checking your gravity, a hydrometer or refractometer? If you are using a hydrometer (and you should be with alcohol present) may want to check it against distilled water, and adjust if necessary.

S04 is notorious for slow fermentations. Might just need some more time, but in my opinion (unless your hydrometer needs to be calibrated) you underpitched.

I have a hydrometer but am using a refractometer. Why do you recommend hydrometer with alcohol present?

Also, if I am going to pitch again, are there any negative effects of this possibly? Would it change the flavor? And how should I do it? Hydrate and pitch?

Thanks again.

 

[tofuguy]

I have a hydrometer but am using a refractometer. Why do you recommend hydrometer with alcohol present?

Are you do a conversion for the refractometer? These are not meant to be used with alcohol present in solution.

 

[paanderson86]

Are you do a conversion for the refractometer? These are not meant to be used with alcohol present in solution.

I am not. Didn’t know that was a thing haha. So am I able to use a refractometer for OG and FG as long as I use a conversion?

 

[paanderson86]

That was the answer. Gravity is currently 1.021. Thank you!

 

[Yooper]

Glad to hear it! I didn't realize you are using a refractometer. I;ve had bigger stouts stop at 1.035 when I mashed at 155. Now I mash them at 152, except for one of my recipes.

 

[tofuguy]

That was the answer. Gravity is currently 1.021. Thank you!

Glad, the conversion factors are estimates. Do a Google search, and you will find the hydrometer is always the best option for fermented beer. A pain since you have to use so much beer.

 

[seatazzz]

Wow glad that helped. Sometimes it seems like we homebrewers need way too many gadgets, but a hydrometer is always your best friend. Refractometers are great for checking your SG but once fermentation starts you really need a good hydrometer. Looks like you've got a great beer coming down the pike!

 

[paanderson86]

So essentially a refractometer is good for brew day so you can do multiple checks on the fly with only a small amount of beer, right? Are the refractometer conversion estimates usually pretty close?

 

[ancientmariner52]

You can use a refractometer to determine if fermentation has finished, but a hydrometer is better for actual, reliable numbers. I use a poor man's pipette (a coffee stirrer) for tiny refractometer samples, and when the gravity stops dropping, I take one big hydrometer sample for the FG number.

 

[RM-MN]

So essentially a refractometer is good for brew day so you can do multiple checks on the fly with only a small amount of beer, right? Are the refractometer conversion estimates usually pretty close?

You can use the refractometer to determine if the fermentation has completed but you can't be certain of the exact FG. If calculating the ABV is important to you or if you want to be certain of the final gravity you have to use a hydrometer as the calculations are an approximation only.