rate of fermentation?

[Ben711200]

There are so many variables that I'm sure that a correct answer is near impossible to provide, but I'll have a go anyway. Please base any answer on 'ideal' conditions. This is my first attempt at AG and I've previously done kits that have been fairly safe in the knowledge that if I do something like a Coopers kit, I can lob the yeast in, come back a couple weeks later and it'll be done. I'm paying more attention now I'm doing AG!

I pitched at 1.050 6 days ago using S-04 and checked the gravity yesterday and it was around 1.020. I looked again today out of curiosity and it didnt' appear to have dropped any further. The lid of the (airlocked) bucket is still getting pressurised and there are a few bubbles on the surface so I assume that it is still going at a slower rate. I was hoping to get advice on what to expect in terms of rate of fermentation at various points. It's obviously very vigorous at the start but when should I expect it to slow down and by how much? Should I do my typical wait to weeks see what it's like then?

Simple questions from a simpleton

[killer]

Hi Ben,

Congrats on your first all grain brew.
For a yeast like S04, typically most of the fermentation is finished in the first 3 days and you'll have 3 steady FG measurements by around day 6. It also attenuates to about 75% so you are probably expecting a FG of about 1012/1013. But there are a few things that could affect the rate of fermentation. For example, did you rehydrate the yeast ? Pitching dry yeast kills about half of it and can slow down the fermentation - but lots of people do that and get good beer. Secondly, the recipe - some grains can leave slightly higher FG's but I imagine you probably used a fairly simple recipe for your first shot at AG ? Thirdly, what's the fermentation temperature ? If it's at the lower end of the recommended range for S04 (about 14° C) it could certainly ferment more slowly especially with this cold weather.
If it really is still bubbling away, you are best just to leave it, try to touch your beer as little as possible while fermenting.
If it stays stuck - you could move it somewhere slightly warmer (assuming that's the problem) or you could give it a gentle stir with a sanitised paddle to try to get it going again. If none of that works you could try pitching another pack of yeast if you have one handy

[OvenHiker]

In my experience, S-04 would bring down a 1050 ale to near terminal gravity in a 3-4 days, assuming 'ideal' conditions. 1020 is a bit high for a typical ale, so I would say it might be stuck. Lots of info on here to try to get it going again.

[darkonnis]

From the sounds of it you've mashed too high.

You don't have to worry about rehydrating yeast too much, unless it specifically states that you should. Fermentis make enough yeast to know what they're on about when they tell you to just empty the packet into the wort. Its possible your temp was a bit off ideal (fluctuating or too high/cold)

If you want a fermentation schedule. i typically leave it 10 days. My last brew I left for 6 weeks (hadnt had the time or the inclination to sort it, though this isn't advised) and no problems. Realistically trying to get it all done n dusted in a week CAN and DOES work, but you're robbing yourself of better beer by rushing it.

As for what you can expect, 3 days with so4 and its done the majority of what its going to do. though that isn't hard and fast and it does very much depend on your recipe, temp, mash temp and pitching rate.

Cooky

[Ben711200]

Thanks all. That's perfectly answered the question and I think that Darkonnis has spotted my newbie mistake in mashing a bit high (more careful temp control and checking the calibration of my thermometer for next time!). I'm fairly sure that my fermentation temp is within the ideal range at around 19-21.

I've given it a tickle with a sanitised paddle and will leave it until the weekend now. Hopefully that will help it go a bit further