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Stuck fermentation - is this what it looks like?

Started by Emot, February 07, 2017, 10:14:34 am

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Emot

So I brewed up a batch of a hefeweizen extract last Sunday (29th January);

500g Munich Malt
2.85kg Wheat Extract
28g Hallertau 60min
WLP300 in a 1.4l starter (a good bit more cells than I think I needed)

BeerSmith said OG would be 1.052 and FG 1.013. Cooled to 17C and checked OG which was 1.055.

I poured it into my fermentation bucket through a sieve to oxidate and pitched the starter, then popped it into the fermentation chamber set to 17C. Took a look the next day (24 hrs later) and the fermentation was well and truly underway. It was my first time using a starter and a fermentation chamber so I figured that was why it was much more active than normal.

2 days later it seemed to have slowed massively but I figured it was nearly finished because my starter was oversized.

Fast forward to last night, I checked FG and it was at 1.015. I thought maybe my hydrometer is off, so I checked that at 20C with tap water and it read 1.003. So correcting my results, OG was 1.052 and FG would be 1.012. I siphoned to a secondary, though my auto siphon let in a lot of oxygen so I gave up on using that half way through and siphoned the rest using a method we won't speak of...

Now this morning, fermentation looks like it kicked off again :-[ - what just happened? Was it stuck fermentation and the added oxygen woke up the yeast? I didn't pup it back in the chamber if that makes any difference.

armedcor

What temperature is it sitting at now? According to White Labs site, the optimal temp for wlp300 is 20-22 degrees. 17 seems awful low for a heffe. My last wheat beer was fermented at about 24 degrees to really bring out some of the esters.

I'm guessing maybe an increase in temp has brought it down a point or two.

Vermelho

Extract always yields a lower FG 1.015 is probably reasonable enough given that it was largely extract based.

Emot

Quote from: armedcor on February 07, 2017, 11:57:10 am
What temperature is it sitting at now? According to White Labs site, the optimal temp for wlp300 is 20-22 degrees. 17 seems awful low for a heffe. My last wheat beer was fermented at about 24 degrees to really bring out some of the esters.

I'm guessing maybe an increase in temp has brought it down a point or two.

I reckon it  would have fallen in temperature overnight anyway to 14-15C or so and when I checked it this morning it would have been at 18C or so.

Quote from: Vermelho on February 07, 2017, 01:59:42 pm
Extract always yields a lower FG 1.015 is probably reasonable enough given that it was largely extract based.

It might make sense that will drop another point or so in that case, though I'm just worried/surprised that it fully took off again this morning after a week in the primary. Do you think that maybe I oxygenated when transferring and that has something to do with it?

Jonnycheech

When transferring into secondary you may have introduced an infection. Depending on the organism these eat sugars that yeast cannot, hence the 'extra' fermentation. You'll know for sure if the beer tastes off.

Where you sanitising everything that touched the beer?
Tapped: FES, NEIPA, CocoIMS, Flanders 2018, Passion Fruit/Peach BW
Fermentors: Raspberry Wheat, Session IPA
Bottled: Cherry Lambic 2019

Emot

Quote from: Johnnycheech on February 07, 2017, 08:19:33 pm
When transferring into secondary you may have introduced an infection. Depending on the organism these eat sugars that yeast cannot, hence the 'extra' fermentation. You'll know for sure if the beer tastes off.

Where you sanitising everything that touched the beer?

Yes anything that came within 2 feet of the bucket got doused with StarSan. I'd be fairly confident I didn't infect it unless areating it might infect it. I'll take a reading again tomorrow evening if the airlock has died down and sample the beer.

In the mean time, I've ramped up the temp to 20C to finish off any last bit of fermentation and let the yeast clean up the beer.