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-   -   Repitching (http://www.homebrewtalk.com/f163/repitching-219163/)

emjay 01-20-2011 01:05 AM

Repitching
 
So I've been helping my brother with a kit beer that has stopped at 1.021 SG. Thing is, this kit is supposed to be a very close imitation to a macrobrew beer and it is far too sweet and underattenuated to even resemble that beer.

The kit was really fresh, manufactured about 8 days before making it, so I figured I could trust the yeast to be adequate, but mrmalty and my cellphone calculator both say the yeast was only half as much as needed.

So I've never repitched before, or even had to, but I've waited long enough to know it's fermenting no further. So my question, because I don't fully get the theory behind repitching when the slurry is probably adequate to throw another beer on top of, is whether people have actually had much success repitching. I don't have access to amylase except for beano right now, which I'd rather not use, and swirling/raising the temp hasn't been enough on its own, so its really my only option. He bought a case of 6 kits, so there's a yeast packet for each one and I can pitch one of those, but if it's a largely frivolous attempt I'd rather save it for his next batch (combined with reusing the current slurry), because if I have to end up buying yeast for a future batch, I'm not sure which would give the result he wants.

Also, if I do repitch, is there any need to re-aerate? I'd think, especially having swirled it a fair amount, that there'd be too great a risk of ending up with oxidized, cardboard-tasting beer. But I've never had to do this before so I have no idea.

I'm sorry if this has been asked and answered a million times before. I tried to search, but right now, my internet access is limited to my cellphone, and my android browser doesn't seem to like the search tool on this site whatsoever.

COLObrewer 01-20-2011 01:57 AM

How long has it been fermenting? Definately do NOT re-aerate!

ksbrain 01-20-2011 02:28 PM

You could also try adding amylase enzyme. There was a post a week or two ago about revitalizing a fermentation with it, and it sounded like it worked well for that person.

emjay 01-21-2011 07:16 AM

Quote:

Originally Posted by COLObrewer (Post 2567236)
How long has it been fermenting? Definately do NOT re-aerate!

No hydrometer movement for about a week. For such a simple beer I don't think I'm overreacting :)

Quote:

Originally Posted by ksbrain (Post 2568302)
You could also try adding amylase enzyme. There was a post a week or two ago about revitalizing a fermentation with it, and it sounded like it worked well for that person.

I pointed out in the OP that my access to amylase right now is limited to Beano tablets, and I'd really rather not use those.

I checked my hydrometer in water and, temperature-corrected, it gave a reading of 1.008 - could the minerals in tap water account for that? I tested it a week ago and it's moderately hard water. And the sweetness of the beer doesn't taste anything like ~1.013 SG. Also, would boiling the kit and additional LME it called for make a difference? I added them to boiling water in the fermenter, but they weren't actually boiled.

I can't believe a kit has me so confused lolů I'd RDWHAHB, but it's not my beer and my brother has 5 more of these kits sitting aroundů I'd like to figure out how to make things go more smoothly rather than waste them all.

Jaybird 01-21-2011 09:29 AM

It is common practice to repitch if you dont see the results you are looking for, loads of people do it with great results. I think I would if I were in your shoes at this point. DO NOT RE-AERATE!!!! Is this dry yeast your using and what kind?? Look on the pack is it expired?? What was the fermentation temp?? What was to OG @ 60*F??
You are working with a living thing here, they may just be done, fat and happy and you may need to bring some more to the party...
Jay

dstar26t 01-21-2011 11:06 AM

Do not use amylase enzyme.
Get some yeast actively fermenting in some wort and pitch it. You could brew another one of those kits (pitch the proper amount of yeast) and add krausen from that kit to this stuck one.

COLObrewer 01-21-2011 11:26 AM

I think it's done. I'd be surprised if it went lower than 1.020, this is usually what happens with these kits where you don't know what went into the extract. There could be a ton of unfermentables. I could send you some juniper yeast, it seems to chew everything down to "overattenuated" but then it's probably not worth shipping to Canada. You could culture some yourself but it will take weeks.

Keep on brewing my friend:mug:

dstar26t 01-21-2011 12:07 PM

Yeah, if it's done it's done, what was the OG? On the next one, pitch the proper amount of yeast and maybe do a fast ferment test along side to see if they match. If it still finishes high you can use a more attenuating yeast or add simple sugar (corn/table/beet) in place of some of the extract.
If you don't want to use simple sugar, another trick is to put a pound of milled 2-row in a grain bag into the kettle (before boiling) with your extract and water and hold it at a low temp of like 146-148 for 30 mins, then remove the grain bag. That will change the fermentability of the wort since the enzymes in the grain will continue to break down the sugars in the extract. You may have to omit some of the extract since you'll get sugar from the grain or you can top off with more water post-boil to get your intended OG.

emjay 01-21-2011 12:32 PM

Quote:

Originally Posted by dstar26t (Post 2571035)
Do not use amylase enzyme.
Get some yeast actively fermenting in some wort and pitch it. You could brew another one of those kits (pitch the proper amount of yeast) and add krausen from that kit to this stuck one.

I like this idea a lot. Seems obvious now that I think about it, but things often do! Thanks.

dstar26t 01-21-2011 12:39 PM

You may want to over pitch the next kit slightly since you'll be removing yeast from it for the "stuck" one.


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