Is it possible to have an unfixable stalled fermentation?

Thor · Jan 17, 2006

I brewed a porter clone recipe in December. OG was 1.070. It stalled at 1.035, and after a week at this SG, I prepared a yeast starter in increments using yeast nutrients, and pitched a pretty healthy yeast cake into the porter, stirring well to get things moving. Or so I thought.

Two weeks later, and no change to SG. What the heck? The airlock is elevated, so something is going on, but with no movement in SG I assume the damn thing is stalled - again.

So, is it possible to have a beer that has sugars remaining but simply refuses to ferment any more? Is there anything I can do, other than drink sweet beer? I have had a couple of batches stall, so I ordered an oxygenation system, but was hoping to "fix" this final (??) challenge.

El Pistolero · Jan 17, 2006

Seems to me that as long as it's been and with the repitch, the sugars remaining must be unfermentable (assuming you've kept it warm of course). Looks like you're gonna have a sweet brew, unless maybe you whip up a bit of hop tea.

Genghis77 · Jan 17, 2006

I think I would tend to disregard the gravity reading. Wait for the bubbling to stop and give it a taste. I won't attempt to pin down a cause, but think things will turn out alright.

Thor · Jan 17, 2006

Bubbling stopped some weeks ago. The airlock is elevated, indicating that some modest fermentation still occurs, but I've seen no bubbling at all.

Denny's Evil Concoctions · Jan 17, 2006

You could try something like a lallemand EC1118 to restart it. You'll already have the esters, etc. from your original yeast and the 1118 will ferment out any fermentable sugars left. Some people do the above for hi gravity barley wines.

david_42 · Jan 17, 2006

Was this AG? Get some iodine and test for starches remaining from an incomplete conversion. If this is the case, get some "digestive tablets" containing Amylase enzymes, add them to the fermentor and re-pitch.

And, yes, sometimes a batch gets stuck and will not complete no matter what you try.

[I haven't tried Beano (r) yet, but I might some day.]