Contamination killed the fermentation?

[ineedahobby]

So recently I finished my third all grain batch and I think I've made a dumb mistake. About two weeks ago while checking on a batch some of the water/trub mix in the vessel containing my blow off tube got sucked into the fermentation bucket.

Fast forward my OG has gone from 1.05~ to about 1.03 and doesn't seem to be dropping any further.

Last weekend I tried introducing more yeast to the batch and it still remains at 1.03.

For reference this is the recipe.

I was pretty excited about this batch and would be a shame to throw it out but an IPA with only 2% abv seems a waste to bottle.

 

[jeffpn]

I don’t think that the splash is the cause of your stuck fermentation. If anything, I’d expect an infection to overferment, not under. What was your mash schedule, time and temp? Did you stir the batch when you introduced more yeast? That may help.

 

[ineedahobby]

Thanks for the reassurance, I checked a few sources to look up what an infection looks like and I think it's in the clear.

As for the schedule I kept it around 160F for about 90 mins.

I didn't stir because I had the impression that it'd have too much contact with the air so I gave it a few shakes after I resealed.

For what it's worth I did sample the beer and it is real close as far as taste to what it should be, just not very much alcohol.

Would it be worth to get a yeast nutrient and a proper liquid yeast starter?

 

[jeffpn]

I think you were on the high end of the mash temp range. Make sure your gravity remains constant for 3 days, package, and enjoy. Next time, mash around 152° or so.

 

[ineedahobby]

I see, thanks for your help.

I am going to let it sit a week and maybe try to move it to a warmer part of the house and I'll revisit it then.

 

[GFHomebrew]

Yep it should move a few more points surley from 1.030.

 

[Hogarthe]

160 mash temp will give you a lot of long chain sugars that are harder for yeast to ferment, leaving your final gravity high. Like the poster above I'd recommend mashing lower next time. I usually aim for 150-152 for an ipa.
Warming it up might help the yeast stay in ferment a bit longer.

 

[ineedahobby]

Alright so revisiting it it doesn't seem to have changed much despite moving the fermentor and giving it a decent shake. A thought occurred if moving the fermentor outside, where it is warmer, but kept in total shade would do the trick and get the yeast to go active again? Or has it already been too long?

Edit: Gave it a shot and moved it outside and it seems to have made a huge difference. Won't leave it outside all the time but for now I'll let it go and then bring it back inside to a place warmer more trafficked.

 

[Group W]

At a mash temp of 160 much of the Beta enzymes were denatured and a lot of starch was likely not converted to sugar. I doubt there is much more sugar for the yeast to eat. Give it a while longer until the gravity doesn’t change for 3 days. Bottle or keg some or all of it and use it to learn/improve that part of the process (i.e. avoiding oxidation). It would have been helpful to have done an iodine test for starch conversion at the end of the mash. You may not have been able to fix it easily, but that test helps narrow down the source of problems. Trust me, a lot can be learned from a bad batch. I have plenty of experience identifying the cause of problem batches. Cheers.

 

[Group W]

This is a nice short read on enzymes.
https://byo.com/article/understanding-enzymes-homebrew-science/

 

[Hawkbox]

Yeah don't stress to hard on it, worst case you pooched a batch of beer and you learn for next time.

 

[Hogarthe]

Make sure...absolutely sure its out of the sun if putting it outside... It doesn't take long to skunk a beer. But skunk beer may be arguably better than underfermented beer...