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-   -   Why are my FGs so high??? (http://www.homebrewtalk.com/f39/why-my-fgs-so-high-152297/)

bce22 12-16-2009 06:43 PM

Why are my FGs so high???
 
Good day Everyone:

I'm about to brew my fourth batch this weekend and I want to make sure I fix any issues in my processes.

My first 2 batches were extract kits, my most recent was a partial mash. The beer i'm brewing on saturday is a PM as well.

My big question is why can't I get my FGs to reach target. This has happened on all three batches so far. Here is some information.

1st batch. Scotch Ale, pitched hydrated S-04 packet. Fermometer read 68 during high krausen then dropped down to 65F. Primary 7 days, Secondary 17. OG=1.077; Measured FG = 1.027. Instructions stated range of 1.020-1.025. Beer Smith states FG should be 1.020. So finished 7 gravity points above target

3rd batch. Sweet Stout, partial mash. Made a 1.1L Starter. Fermometer read 68 during high krausen, then dropped to 64-65F. Still in Primary (so far 11 days), Leaving for 3 weeks. OG=1.064, SG = 1.025. AHS states OG should be 1.059, beer smith 1.060. Final Gravity should be 1.015-1.017. So finished 10 - 12 gravity points above target

My 2nd batch finished a higher than expected FG as well, however I don't have my readings available to give you the details.

So I'm trying to do everything right by my yeast. I have a stirplate, my basement keeps a very steady temp in the mid 60's and I even have been using a stir bar that attaches to a cordless drill that is used to degass wine for aerating my wort prior to pitching the yeast.

What could be causing my fermentations to crap out prior to getting down to expected FGs? Is there anything i can do to try to get my Sweet Stout down to 1.015 from 1.025 11 days in? What can I do on this next batch to give me a better chance of hitting my final target?

Thanks in advance!

Brad

TipsyDragon 12-16-2009 06:49 PM

many things can affect fermentation. the temps you mash at can affect the fermentability of your wart. the temp you ferment at can affect how fast you get to your FG. it sounds like you aerate enough but that to can also affect fermentation. also if you don't pitch enough yeast to begin will not get your target FG.

scinerd3000 12-16-2009 06:49 PM

are you pitching at high krauzen of the starter or letting it ferment down and then adding into the wort? Second- what temperature are you steeping the grains at? If your doing them higher than about 155 then that could impede the ability of the yeast to ferment closer to dryness. The only thing you can do now if they are really done fermenting is to add a different type of yeast. Some people use champaign yeast but it could go lower than your anticipating. If you havent tried yet, rouse the yeast and trub at the bottom and ove to a slightly warmer place to see if you can get it to restart although most of the time i have bad luck with that method...

oh and whats yeasts did you use? just for clarification. some can be problematic

Pharmguy 12-16-2009 06:58 PM

Pretty big beers, your first beer had an OG of 1.077 and it was only in primary a week? Are those beers exploding now? :) Your 3rd batch may just need more time!

bce22 12-16-2009 07:00 PM

Quote:

Originally Posted by scinerd3000 (Post 1746221)
are you pitching at high krauzen of the starter or letting it ferment down and then adding into the wort?

I made the starter and left it on the stir plate for 24 hours. I placed in the Frig the night before and decanted off most of the starter wort in the morning, left it out to adjust to room temperature for about 6 hours and pitched it into my cool, aerated wort.
Quote:

Originally Posted by scinerd3000 (Post 1746221)
Second- what temperature are you steeping the grains at?

This was my first partial mash so I had a little trouble maintaining my temp. I mashed in at 154F and left it my stockpot on the counter covered for 1 hour. After the hour when I checked the temp it had dropped to approx 145F after 60 min. I then moved my grain bag to my sparge water at 168F for 10 minutes.
Quote:

Originally Posted by scinerd3000 (Post 1746221)
The only thing you can do now if they are really done fermenting is to add a different type of yeast. Some people use champaign yeast but it could go lower than your anticipating. If you havent tried yet, rouse the yeast and trub at the bottom and ove to a slightly warmer place to see if you can get it to restart although most of the time i have bad luck with that method...
oh and whats yeasts did you use? just for clarification. some can be problematic

I'll answer the last question first. My sweet stout used White Labs London Ale 013. I used Mr. Malty to determine starter size.

I do have an extra packet of Safale S-04 dry english ale yeast. Should I pitch that? My basement is the most temp stable place in my house. The rest of the rooms are will be cooler than 65F during the majority of the day and late night and maybe get up near 69-70F during the morning and evening when people are home. My basement stays constantly between 64-66 all day long.

Zen_Brew 12-16-2009 07:01 PM

Everything you have posted in your process looks good. The ferm temps are good, aeration is good.

Both those beers are a bit on the big side which always puts more stress on the yeast. Did you add any yeast nutrient to the wort? That can sometimes help get them in top shape to finish a big ferment. Also sometimes for a bigger beer a second aeration once fermentation begins, at say yeast pitch +12-18 hours can be helpful. This step is optional, and obviously you must take care not to introduce nasties into the beer, but the additional oxygen keeps the yeast reproducing a bit longer up front for a larger, healthier colony. I don't know that I would put the drill stirrer back in, but a light shake and swirl can get more oxygen in the wort.

bce22 12-16-2009 07:02 PM

Quote:

Originally Posted by Pharmguy (Post 1746250)
Pretty big beers, your first beer had an OG of 1.077 and it was only in primary a week? Are those beers exploding now? :) Your 3rd batch may just need more time!

Yeah I left the Scotch ale in the primary only for a week and then close to three weeks in the secondary. I needed my primary for a second batch at that time. Since then I bucked up and bought more buckets/carboys.

No exploding beers.

bce22 12-16-2009 07:04 PM

Quote:

Originally Posted by Zen_Brew (Post 1746265)
Everything you have posted in your process looks good. The ferm temps are good, aeration is good.

Both those beers are a bit on the big side which always puts more stress on the yeast. Did you add any yeast nutrient to the wort? That can sometimes help get them in top shape to finish a big ferment. Also sometimes for a bigger beer a second aeration once fermentation begins, at say yeast pitch +12-18 hours can be helpful. This step is optional, and obviously you must take care not to introduce nasties into the beer, but the additional oxygen keeps the yeast reproducing a bit longer up front for a larger, healthier colony. I don't know that I would put the drill stirrer back in, but a light shake and swirl can get more oxygen in the wort.

Thanks for the info. I have yeast nutrients that I used in the starter. I ordered 2 bags instead of one so I have enough yeast nutrient in the house to last like a decade.

Would it be worthwhile to put in a teaspoon of yeast nutrient at this point and shake up the fermenter?

Zen_Brew 12-16-2009 07:13 PM

For 5.5 gallon batch I usually put about 2 tsp of nutrient in the boil about 10 mins to flameout. I think once the yeasts are pooped out at the end of a ferment they get little benefit from the addition of nutrient. Sometimes yeast energizer, yeast hulls, or Femaid K (a specific brand of nutrient) can help a sluggish of stuck ferment, but not always and you can end up with some flavor contributions from them if the yeast don't use them. If the gravity is no longer dropping I don't know that I would risk it.

For the beer that you only had in primary for a week, you may have taken it off the primary yeast cake a bit soon. At this point the only thing I would try would be to warm the beer up to about 68-70 and lightly stir the carboy to rouse the yeast.

maida7 12-16-2009 07:36 PM

I think your fermentation temp dropping toward the end is the main problem. The English yeast strains you have been using have a flocculate at the drop of a hat. If your temp starts to drop toward the end the yeast will fall to the bottom and be done. Also, English strains are not know for being highly attenuating. Switch to American ale yeast on your next batch and see what happens.

Ideally you start cool 60-64F
Warm slowly over the first 3 days to 66-72
then keep it warm until you reach the proper ending gravity.


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