pitch more slurry for a stuck fermentation?

[drunkinThailand]

I brewed up a Porter last Saturday, pitched some harvested yeast that I had made a quick vitality starter with, but when the airlock activity slowed quicker than I thought it should I took a gravity reading yesterday, Wednesday.

Original gravity was 1.070, and I was hoping final gravity would be down to at least 1.017. However when I checked it was only 1.029.

I am going to check again on Friday - if it is still inching down I will let it keep going, but if it is stuck can I just pitch some more of the harvested slurry that I have? When I tested the hydrometer sample it tasted fine, if that matters (just too sweet).

If I can, do I just put 1.029 into the calculator to figure out how much yeast to pitch?

 

[ncbrewer]

It's Friday - did you get another gravity reading?

 

[IslandLizard]

No slurry won't work, you would need to pitch active yeast, preferably at high krausen.

Which yeast did you use?

Give it another week, at a bit higher temps (75F) if possible. A little rousing may help to bring the yeast back up from the bottom. If you have CO2, use that to rouse.

If it still hasn't budged after another week make a new large starter and pitch when that is at high krausen. Alternatively, you can cold crash it when it's at high krausen, then decant, warm back up and pitch with a gentle stir/rouse to prevent air getting mixed into your beer and oxidizing it.

 

[drunkinThailand]

Thanks for the help

I have been busy, just took another gravity reading - 1.026. I've raised the temp a few degrees, will rouse daily and wait a few more days, then if it isn't going down i will pitch a starter at full krausen.

If making a starter out of slurry, should I just use 100 billion cells and the amount of wort from a calculator, or if I have more cells available should I use more? I've never made a traditional starter before.

thanks again