Slow fermentation - possible causes and solutions?

[drf]

Bit of a long one this! Just after some advice....

I've got my second every brew on. It's a Munton's Gold Docklands Porter (a 2 can kit). Yeast pitched last Saturday morning (so 9 days ago). Not sure of the OG as I couldn't read it properly as I didn't have enough in my trial jar and couldn't see the meniscus through foam, you live and learn though! It was probably around 1.045. Pitched at 27C with Safale-04 rather than the kit yeast. Fermentation got off slower than I thought it might, but it was bubbling nicely by 24hrs later. Fermentation temperature will have been held pretty much at 20C as I jave the FV sitting in a box full of water with a fish tank heater in it, which has done the business.

By yesterday bubbling had slowed to a burp every 5 mins or so and I decided to take a hydrometer reading. It's around 1.024 which I thought was a bit high for this time in the process, with the intention of bottling this Sunday (that's day 15 after pitching). I gave the yeast a gentle rousing which increased bubbling frequency, although it's dropped off quite a bit again by this morning.

In my first brew I had a similar slowing at a relatively high gravity, I thought that might have been due to temperature drops as that one was only wrapped in a blanket, but I know this one has been pretty constant temperature.

So, what should I do, and how might I be able to get better fermentation in the future? My intention is to take another gravity reading on Wednesday to see where things are (tomorrow isn't a possibility and I don't see the point of doing it today).

The wort had decent initial aeration I think (dropped Campden-treated water from another FV into it, and got a bit of foaming). I had rehydrated the yeast, getting the wort ready took a bit longer than expected so maybe the yeast was hanging around a bit longer than ideal but not by too much. My wort at 27C might have cooled down quicker than if it was just left to the air as I put my (20C) water jacket round it just after pitching.

Might the high flocculation of Safale-04 cause fermentation to slow quicker than some yeasts, if it hasn't got off to a really flying start? Might future brews benefit from an earlier rousing? I notice that Graham Wheeler's book recommends an early rousing/additional aeration after 24hrs. I'm always loath to interfere too much with the beer though!

Any pointers?

TIA

Chris

 

[tan]

noob question: i assume the kits have yeast nutrient, but would that be in the yeast sache you didnt use or in the can of other ingredients you did use?
(sorry i cant help, but i recently got better ferm rate using nutrients (non-kit brew) and wondered)

 

[Rich85]

Have a look at:

http://www.fermentis.com/fo/pdf/HB/EN/S ... -04_HB.pdf - Information on the S04 yeast

http://www.muntons.com/downloads/common ... s%20v2.pdf - Useful document covering loads of problems that you might have including stuck fermentations.

Loads of people including myself have had problems with the Muntons kits sticking around the 1.020 mark. Have you checked the temperature of the wort with a thermometer or are you just relying on the thermostat setting of your aquarium heater? Could be that the thermostat isn't accurate and the wort is too hot or more likely too cold.

I have got a Muntons Smugglers kegged at the minute which stopped at the dreaded 1.020. I added yeast nutrient and left it for a week and still nothing. I assumed that because I had got the FV well insulated and the weather was nice that the temperature would be fine and so didn't think to check it. It turned out that it had cooled to 15c and the yeast must have stopped working so I put in an aquarium heater, gave it a stir and after three days it had dropped to 1.014.

Hope this helps

 

[Sean_Mc]

Just my two pence worth, but I think with all kits, especially the two can kits you really need to aerate them before pitching the yeast.
With the one can kits you give them a bliddy good stir to get the sugar dissolved and less so with the two can, no need for sugar kits.
I found if you stir and aerate them, then pitch with hydrated yeast their less prone to sticking around the 1020 mark.

I was recently given a wherry kit ( mothers in-law never listen :grin: ), but due to shop stocks or production line mishap it had no yeast sachet. I contacted Woodefords and they supplied me with 5 packets of yeast (Munton's premium). One for the kit and used two for an AG stout. The kit preformed okay, finished at 1012.
The stout with the wherry yeast tasted good though to my uneducated taste buds :thumb:

 

[drf]

Just my two pence worth, but I think with all kits, especially the two can kits you really need to aerate them before pitching the yeast.

Well, I gave the water a decent aeration the night before, pre-Campden treatment. Most of the water was then dropped into the kit from work surface height, which was generating a bit of foam so there was some extra aeration there. Maybe I could've given it a bit of a whiz with the electric drill at that point though. I'm going to take another gravity reading tonight, and give it another bit of a stir. Hopefully it's dropped a few points since last time!