That's an interesting point Hutch.
My understanding was to pitch the yeast at as close to 25deg as possible and do all things necessary to keep it there ("Home Brew" - by Willie Simpson).
Are you suggesting pitching at 25 and cooling - or are you suggesting that I pitch at 20deg also?
What do others have to say on this point?
My experience has been to pitch the dry yeast at around 24-27 degrees, and then to whack the fermenter in the fridge to cool it down to below 20 (normally aim to keep it at 15 degrees for the rest of the fermentation). By pitching the yeast at a higher temp, I am allowing it to multiply (I don't culture the yeast if I use the packet yeast) before it starts making alcohol. If I am using some cultured yeast (like from a Coopers pale Ale), then I pitch it at the lower temp of around 15 degrees as there should be enough yeast in there to start making alcohol right away, instead of needing to multiply first.
At the very end of the fermentation, I take the fermenter out of the fridge and let it warm up to around 27 degrees for a day to help the yeast finish off anything they might have left behind. This is because by this point, the bulk of the fermentation would have been completed, and there is very little risk of 'off' flavours being produced by higher fermentation temperatures. This can result in a nice dry finish for your Cervaza.
I would also point out that once it has had a day at 27 degrees, I crash chill the fermenter down to around 2 degrees in the fridge to help any yeast drop out to clear the beer. Although I keg mine from there, if you bottle it will still help to do this to clear the beer, and it will still leave enough yeast in suspension to bottle condition. If you have another fermenter available, it is good to rack from the first cold fermenter into another, and then to add the whole of the sugar you will be using to bottle condition to the second fermenter. Dissolve the amount of sugar (typically I think to be around 180-200 grams for a 23 litre batch - confirmation anyone?) in a small amount of boiling water, and add it to the second fermenter, and stir. Each bottle will have exactly the same amount of priming sugar in it, and then let them condition for a good month at least.
Hope I haven't confused you, but search for some of this info in the articles section at the top of the page and you can make up your own mind!
Crundle