Will more yeast help?

[Khirsah17]

I recently just brewed an AG beer that had an OG of 1.112, and it has fermented down to about 1.042. It's only been in the fermenter for about 5 days, but it seems like all activity has stopped and there's no krausen on the top. I would have liked to see it come down more. I am using White Labs Super High Gravity Ale Yeast (WLP099), and they say that this yeast should get greater than 80% attenuation. Right now, based on my numbers, I only have about 63% attenuation. That's not all that great.

Does anyone have any ideas why this yeast didn't live up to it's potential? I had the fermenter in a temperature controlled fridge set at the range of optimal yeast temperatures.

Also, I just so happen to have another starter of WLP099 going right now that I was planning on using in another brew. What would happen if I added this starter to my fermenter? Would the "fresh" yeast continue the fermentation down closer to the target SG? Do I have to worry about any weird off flavors if I did this?

Thanks!

 

[FlyGuy]

That's a big beer -- did you do a BIG starter to match it? Many even do a low gravity batch first, and then pitch their high gravity brew on top of the yeast cake so that there is enough yeast for the ferment.

It sounds like your yeast are spent. Repitching that fresh starter will probably get you down closer to your target FG. If the yeast is fresh, you have no reason to worry about off flavours introduced by re-pitching, especially if you decant your starter.

FYI - here is a good link to a calculator to help determine how much yeast one needs for different gravities of beer, in case you hadn't seen it already:
http://www.mrmalty.com/calc/calc.html

 

[homebrewer_99]

Rouse your yeast. Sounds like it went to sleep.

Give the brew a quick swirl (one time around the bucket slowly) with a sanitized stirrer.

Check again tonight. If it's still asleep repitch.

 

[Khirsah17]

Yea, I tried giving it intermittent swirls for the last day or so, and still nothing. I didn't use a stirrer, because it is in a carboy, so I can't reach it. I just shook the carboy a bit.

I made a starter using about two pints and about 1/3 lb of DME. Then it sat in the fridge for about 3 weeks before I actually found time to brew. I decanted and added another two pints of water, this time with 0.5 lbs of DME. The resulting activity was so strong it blew out my airlock. I figured it was ready to go. However, that website says my starter should be in the volume of LITERS. Wow. I suppose next time I'll make an even bigger starter.. muhahaha.

For now, it looks like i'll be repitching.

 

[Yeast Infection]

what temp did you mash at?

 

[Khirsah17]

Well, thats something that may contribute. When I finished adding the strike water, the temperature of the mash was like 163. I tried mixing, and I was finding pockets of dry grain, but my spoon wasnt long enough to get to the bottom of the mash tun. So I ran the store and bought a spoon, but it took about 40 minutes to get home and stir. After that was said and done, the temperature was about 155. I left it in there for another 40ish minutes. So there may be more unfermentables than i give credit for?

 

[FlyGuy]

LOL -- yep, that is going to affect things. It sounds like something I would do!

You might still try adding some yeast, but you really aren't going to get down to 80% apparent attenuation.

 

[grnich]

How much aeration did you give the wort before pitching? Big beers need big aeration. For a hot mash like that, doesn't sound like you're going to get it down any more.

 

[Denny's Evil Concoctions]

If you try the rousing and or repitching and you donlt get any lower try some lavlin ec 1118 chanpnge yeast. If it's due largely to unfermentables this yeast should ferment out anything fermentable that's still left.

You could add some amylase enzyme as well.. But that's a lot like beano.

Also, you could pitch new yeast and aerate as a last ditch effort.

It's just ahrd to ell if this is burnt out yeast or a high mash temp.

 

[Khirsah17]

Ah, the joys of learning how to brew AG beers. Hopefully next time Ill be more prepared and wont let my mash temperature get out of control. However, I was thinking along the lines of, well, it mashed hot for a while, but I eventually got it down to 155 (was my target mash temp). So if i leave it there for a while, it'll be a longer mash, but should turn out the same as if it was at 155 the whole time. The only thing I lost was time. Is there anything wrong with the thinking?

I aerated the heck out of this thing for about 35 minutes, but i dont have aeration stones or anything. Let's say I siphon to a secondary and remove the beer from most of the yeast. Then I aerate by shaking it up for a while before repitching... will I have oxidation effects?

Sorry for all the questions, but this is slightly more advanced than I know. Good stuff though!

 

[Got Trub?]

Ah, the joys of learning how to brew AG beers. Hopefully next time Ill be more prepared and wont let my mash temperature get out of control. However, I was thinking along the lines of, well, it mashed hot for a while, but I eventually got it down to 155 (was my target mash temp). So if i leave it there for a while, it'll be a longer mash, but should turn out the same as if it was at 155 the whole time. The only thing I lost was time. Is there anything wrong with the thinking?

I aerated the heck out of this thing for about 35 minutes, but i dont have aeration stones or anything. Let's say I siphon to a secondary and remove the beer from most of the yeast. Then I aerate by shaking it up for a while before repitching... will I have oxidation effects?

Sorry for all the questions, but this is slightly more advanced than I know. Good stuff though!

Makes sense but isn't correct. From the time you add the hot water your in a race against time. The mash conditions used to make beer are not ideal for either the B-amylase or A-amylase but rather a compromise so both will work to a greater or lesser degree. Both are denaturing over time, particularly the B-amylase at high temps. I'd guess your wort will be slightly higher in unfermentable sugars then it would have been if you had hit your strike temp.

Re-aerating should be your last option as it will oxidize your beer at this point and shouldn't be needed if you repitch with enough healthy yeast. You don't need them reproducing you want them fermenting...

 

[Denny's Evil Concoctions]

Order some amylase enzyme. If you hit high like this and can't get it down quick enough, adding amylase after you get the temp down will give you a new batch of enzyes to munch at the beta level.