My experience is Safale S-04 (blue packet) stops working once you get down below about 15 degrees. I had a beer made from S-04 that I bottled and left in the back shed during winter where the temp was around 15 degrees and it didn't carbonate. After 8 weeks it was still flat. I moved it to a warmer spot (around 20 degrees) for 2 weeks and it carbonated normally.
Keep in mind that the thermometer on the side of the fermenter is affected by the ambient air temperature as well as the brew temp. Also the liquid at the sides of the fermenter can be cooler than the liquid in the center so the fermentation may be a bit warmer than the thermometer leads you to believe.
I certainly noticed the difference when I switched to Safale and liquid yeasts. I made pizza bases with the Coopers yeast I had left over.
BTW, was the Coopers lager kit with 1kg of malt a bit sweet? I tried this years ago and it was sickly sweet for my taste. I found that a can of Coopers lager with 500g of malt made to 17 or 18 liters produced a full malt beer with the right balance of bitterness/sweetness.
[post="120862"][/post]
