mick may said:
You might be being a little hard on the kit. Have another go with the rehydration technique, it makes a big difference. One thing missing from it though was the need to bring the yeast to within a couple of degrees c of the wort temperature, up to 5c you might get away with, but the closer it is the better. Make sure whatever you use to transfer a few drops of wort to the successfully rehydrated yeast is sanitised and you will be close to 100% rehydration of the viable yeast, using the cooled to fermentation temp wort will help acclimate the yeast into its new environment, bit like holding its hand at the school gate.
Also remember that a fast start to fermentation is not necessarily the "good" sign it is passed off as. The yeast needs to absorb all the oxygen first, as it is at this stage replicating like mad to provide sufficient yeast to get the job done. It will do this until the oxygen is depleted, if there is insufficient oxygen it will start very quickly often leading to too rapid cell growth that leaves the cells in less than optimum condition for the rest of the fermentation.
