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hindey19

stuck fermentation-what to do

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So I brewed my first ag brew on June 30th. Nothing fancy, basic amber ale. 1.050 OG and used Safale US05, fermented for 16 days at a relatively consistent 72.
Went to bottle tonight, checked gravity and its at 1.025, about 0.01 above where I expected it to be at.

Is there anything I can do this far into it to salvage the beer and restart/continue fermentation?
This is my first ag brew and I really want it to go well.

Here's the recipe I used-
http://www.brewtoad.com/recipes/american-amber-first-ag

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Stir up the trub to get the yeast going again?
Wouldn't this create off-flavours, aerating the beer?

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"RickBeer" post=387117 said:

Give it a stir.

That would be my advice also. That and give it an additional week or so. But stir it gently.

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What was your mash temperature and for how long?
What temperature did you pitch the yeast?

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Gave it a gentle stir and put it back. I'll check back in a week.
Thanks guys.

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This is the same situation I'm currently dealing with. I stirred up the trub gently, not hard enough to splash or make bubbles, so as to avoid aerating it. Going to check on Thursday if it helped, but it's pretty much the same issue. I was expecting an FG of 1.012, and when I checked, I was at 1.022. 10 points off, using US-05 just the same. The mash temps likely produced less fermentables than desired so the FG may not go down. Regardless, there will be beer, just less potent than expected.

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Well hopefully it works out for both of us Phil.
I saw your post just after I posted this one.

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Try 'rousing the yeast'; AKA stir it up. Might aerate it some, but usually helps. What temp did you mash at?

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Guest

When this happens to me, I drop in a pinch of yeast nutrient I keep on hand and very gently stir the trub back up into suspension. Usually works.

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"hindey19" post=387259 said:

For those asking, I mashed at 155-160F for 60 minutes.

That's a fairly high mash temp...

It's likely that you produced a wort with a lot of unfermentable sugars...

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What should it generally be at?
If it makes any difference, I think the majority of the 60 minutes was at 155.

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"hindey19" post=387275 said:

What should it generally be at?
If it makes any difference, I think the majority of the 60 minutes was at 155.

Well, it can be 146-160*F but there is a big difference over a small number of degrees...

Here's a chart that shows how fermentability drops as temperature rises.

Note that the percentage of dextrines rises as well providing more mouthfeel as mash temps rise.

EDIT: So, if you think you were at 155*F 'most' of the time (and maybe as high as 158-160*F), your resulting wort would be 75-80% fermentable according to the chart.

You can figure that your yeast might average 75% attenation of that 75-80% (fermentable portion of your wort)...

That's gonna leave 25% of the fermentable wort unfermented, as well as the 20-25% of the total wort unfermented, resulting in a higher final gravity. In other words, a greayer amount of unfermentable sugar will remain. Also there will be more dextrins... And less total ABV. This will result in beer that is sweeter than expected, with more mouthfeel and less buzz... But it WILL be beer none the less...

:)

6554081F-7E6E-4867-9820-BF77F94FC5BF-646

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I'm currently fermenting an Oktoberfest that I used a decent amount of Caramunich in (1lb plus 3.3 lbs of Amber DME). It's also my first go around with US 05. I've been keeping my fermentation temps in the low 60's, no higher than 64 for the first week. I'm aiming for an FG of 1.12 myself. I'm nervous as I've been told it's tough to get all of that caramunich broken down to hit that FG. I'll let the yeast do its work but I'll keep these posts in mind if I need to try to get my numbers down a little further. Can you simply swirl the fermenter or is it better to sanitize a spoon and gently stir it?

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If your mash was between 155 and 160, particularly if it was closer to 160, your fermentation is probably done. If you were looking for a malty beer with a lot of body, congratulations you have achieved it. Also the last 3 brews I did with 05 came out way under attenuated. That's why I switched to BRY-97. I haven't had any issues with that yet.

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That recipe doesn't have you doing any bittering additions.

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Thanks everyone for the help.
This was my first AG so there's still a lot to learn, and this was definitely a good learning experience.

I'll check the gravity again in a couple days and if it hasn't changed I'll cold crash (finally got a dedicated fridge) and then bottle.

Gymrat - you're right, I didn't have any bittering hops. I probably should have. I'll see how it turns out and adjust if I decide to brew this again.

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"BigPapaG" post=387284 said:


6554081F-7E6E-4867-9820-BF77F94FC5BF-646


Is there a bigger version of this graph I can check out?

Edit: Nevermind - Google to the rescue
http://missionarybrewer.files.wordpress.com/2012/02/enzyme_activity_one_hour_mash.jpg


So it seems that 153 is the ideal mash temperature then, eh? Unless you want to specifically get more mouthfeel, then you mash higher?

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"hindey19" post=387303 said:

"BigPapaG" post=387284 said:


6554081F-7E6E-4867-9820-BF77F94FC5BF-646


Is there a bigger version of this graph I can check out?

Edit: Nevermind - Google to the rescue
http://missionarybrewer.files.wordpress.com/2012/02/enzyme_activity_one_hour_mash.jpg


So it seems that 153 is the ideal mash temperature then, eh? Unless you want to specifically get more mouthfeel, then you mash higher?

Ideal mash temperature depends on what you want from your beer. In general, lower temps 148-152 will give you a dryer thinner beer with a higher ABV, which is good for showcasing hops, Higher mash temperatures will give you a more robust heavy bodied beer, which is good for showcasing complexity of malt flavor.

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As always, thanks for the help.
This has been extremely enlightening. I've never actually read what different temperatures do to grains while mashing before.

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If rousing the yeast (stirring the trub bed) doesn't work, you can also try adding more yeast, ideally from a different lot or lab in case the problem yeast related. I've never had an under attenuation with the 05, but I have had a recent one that only attenuated around 73%, when I typically get close to 80% from it (I aerate the snot out of the wort, which helps a lot).

For you to have an apparent attenuation of only 50%, I 'm inclined to think the problem is not so much with your wort as with your yeast health. If I see an attenuation over 60% , I generally don't worry about it--just chalk it up to the vagaries of the beer gods. One of my best beers only attenuated that far, and when I tried to replicate it with a fermentation that was normal, the beer was not nearly as good.

I've only had one truly stuck fermentation. Tried rousing the yeast almost daily for a couple weeks, warming the fermenter--basically the usual recommended easy fixes. After a month or so in secondary, after dropping in gravity by just a point or two, I rehydrated a dry yeast (the original was a White Labs trappist yeast) and gently poured it into the carboy. The reaction was immediate and a sight to behold. It literally started refermenting within seconds, and finished in the proper range within a week. Just something to try if other methods fail.

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Would there be any negative affects if I pitched more yeast and it really was finished fermenting, giving the new yeast nothing to do?

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"hindey19" post=387551 said:

Would there be any negative affects if I pitched more yeast and it really was finished fermenting, giving the new yeast nothing to do?

Does your beer taste sweet at all?

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I'll have to have a taste when I get home tonight.
I'm guessing if it tastes sweet, then there are still sugars in there and I should pitch another pack of yeast.

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I just went ahead and bottled mine. Gravity only dropped 1 point to 1.021 so I don't think it's going any lower. Gonna attribute the high FG to the mash temperature. I did see some matter on the outside of the keg so the fermentation seems to have actually blown out a bit. Wonder how yours turns out after pitching more yeast.

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"hindey19" post=387556 said:

I'll have to have a taste when I get home tonight.
I'm guessing if it tastes sweet, then there are still sugars in there and I should pitch another pack of yeast.

Exactly!
I have had two beers that finished at 50%, neither had any sweetness at all, bottled both, no issues with either and it has been months. Both were S 05 yeast. I switched to BRY-97 for my American ales.

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