The first thing to remember is that yeast is alive and that Happy Healthy Yeast makes Better Beer.
What yeasts to use?
Beers/Lagers have yeast types or strains specific to a kind of beer or even to a brand of beer. This particular strain plays a big part in making a particular brew what it is, for instance Courage Directors would not be the same if brewed with something other than their own yeast. So it’s important to get the right yeast for the recipe or type of beer you’re brewing.
Physically we buy yeasts either dried in packets or in liquid form, both have their advantages. Dry yeast is cheaper and more convenient were as liquid yeast offers a much greater range of styles/strains and is said to be truer to the style of beer. However the range of dry yeasts is improving.
There’s something else to consider, how much yeast to you need to add (pitch) to your wort? The two commonest causes of slow (long) fermentations are insuficient healthy yeast and fermenting too cold.
This depends on the volume you’re planning to ferment, the SG of the wort and a number of other factors. Fortunately MrMalty has a calculator that’s easy to use and works it out for you.
Taken from the Fermentis Blog :-
Before dry yeast can start fermenting, they need to absorb the water they lost during the drying process.
Yeasts are living organisms and rehydration temperature is critical for good yeast performance.
Fermentis recommends that top fermenting (ale) yeasts are rehydrated at a temperature between 25-29°C (77-84°F) and that bottom fermenting yeasts (lager) are rehydrated at a temperature range of 21-25°C (69-77°F).
Rehydration is done in a vessel outside the fermenter. The objective is to reduce the lag phase : the time necessary for the yeasts to start fermenting sugars to alcohol after inoculating the wort.
- Rehydration is a simple procedure.
- Rehydrate the yeast in 10 times its weight of water or wort.
- Gently stir.
- Allow a 30 minutes rest.
- Pitch the resultant cream in the fermenter.