Stuck. Again!

[dopejack]

Getting a bit fed up with this. Hope some-one can help before I chuck it all in! Started a Porter, with an O.G. of 1053, began its fermentation really quickly and went mad, overflowing the F.V., then after about four days stopped, stuck at 1020 and won't budge. I waited a couple more days, then gave it a good stir, two more days, nothing. Sprinkled in some Safale 04. Three more days...nowt. Same O.G., funny looking film on the top, not a nice smell. This one is destined for the drain, but I'm hoping some-one can tell me what went wrong so I can try to avoid it next time.
Thanks

[Chappie519]

What temperature are you pitching the yeast at? What temp is it fermenting at? Waht yeast are you using SO4?

It sounds like the yeast may be getting stressed at the start of fermentation with it being too vigerous and warm. This would then cause it to struggle to ferment all the way. Better in homebrewing to go lower witht the fermentation temp and have a long slow ferment. ~ less hangover

The film on top sounds like a bacterial contamination!? How does it taste?

[dopejack]

Hi,
Actually doesn't tast too bad! Little bit sweet, as you'd probably expect. Pitched it first of all with Nottingham, and I have an immersion heater in the wort as my kitchen is pretty cool ( missus won't let me keep it anywhere else, she is pregnant, so she is being pretty tollerant letting me brew at all!!). Just sprinkled the SO4 on, didn't want to go to any more trouble as I've all but given up on this batch.

[harvs]

Just a thought - have you checked what temp the immersion heater is maintaining the wort at? I have an immersion heater, and found it was set at a pretty high temp as default - had to play around with it for a while to get it set to 20 degrees. (The small temp control knob is not particularly easy to adjust accuratly).

[SiHoltye]

I'd agree with checking the fermenting temperature, also I'd pitch 2 packs of S04 (22g) into 5G wort over 1.048 making sure I'd rehydrated first in 100ml of boiled and cooled water. Also consider mash temperature. Over 69°C and you'll leave a lot of difficult to ferment sugars in the wort resulting in a high final gravity. I'd aim for 65-68°C depending on the beer style.

Hang in there.

[Bru4u]

I'd agree with a high fermentation temp, don't give up, it's an easy problem to solve

[alefric]

I would agree with the above posts and as for the film it sounds very much like an infection.

Andrew

[stevezx7r]

I wouldn't be too sure on it having an infection due to the film on top. A lot of beers I've made have had a thin, grey film on top and the beer was fine.

Without pics it's hard to be certain - don't bin it 'till it's Sarsons

[Calum]

The other thing to check is you mash temp (you didn't mention). I had a problem last year when my trusty electronic thermometer went on the blink and I used a cheapie glass one instead. I had a couple of beers that were not fermenting out which was pretty annoying. Suspicion then turned to my cheapie thermometer, I took it around to mates to compare to his and it was around 3C out so I was mashing at too high a temperature. As soon as I invested in a more reliable thermometer the problem went away.

[PMH0810]

Having read Graham's new book I aerate firmly before pitching and then again after about 12 - 18 hours. This appears to have removed my stuck fermenation problem.

[BarryNL]

Having read Graham's new book I aerate firmly before pitching and then again after about 12 - 18 hours. This appears to have removed my stuck fermenation problem.

I really find the best technique is just to keep it simple - there should be no need to do a second aeration on a 1.050 beer - in fact, I don't even bother on my 1.090's any more. Just make sure the wort is well aerated before pitching then rehydrate the yeast in 10ml water per 1g yeast (i.e. about 115ml for a pack of S04) at about 25 deg.C for about half an hour, then pitch it and leave it alone for a couple of weeks. The key is pitching enough yeast - at least as much as the calculator over at Mr Malty recommends.

Also, a dark beer may well finish high - all the crystal and roast grains contain a lot of unfermentable material. I've had stouts finishing around 1.025 (from 1.075) and being perfectly dry and drinkable. In fact, I'm expecting my next Russian Imperial will finish around 1.035