As I mentioned earlier, the dry ale yeast strains tend to be fairly similar, attenuative and clean tasting, performing well for most ale styles. To illustrate with a very broad brush, there are Australian, British and Canadian strains, each producing what can be considered that country's style of pale ale. The Australian type is more woody, the British more fruity, and the Canadian a bit more malty. Fortunately with international interest in homebrewing growing as it is, dry yeast strains and variety are improving. Some of my favorites are Nottingham (DanStar), Whitbread (Yeast Labs), and Cooper's Ale.
Here is an incomplete list of dry yeast strains and their characteristics:
Cooper's Ale (Cooper's)
All-purpose dry ale yeast. It produces a complex woody, fruity beer at warm temperatures. More heat tolerant than other strains, 65-75¡F; recommended for summer brewing. Medium attenuation and flocculation.
Edme Ale (Edme Ltd.)
One of the original dry yeast strains, this produces a soft, bready finish. Medium flocculation and medium-high attenuation. Fermentation range of 62-70°F.
London Ale (Lallemand)
Moderate fruitiness suitable for all pale ale styles. Medium-high attenuation and flocculation. Fermentation range of 64-70°F.
Nottingham Ale (Lallemand)
A more neutral ale yeast with lower levels of esters and a crisp, malty finish. Can be used for lager-type beers at low temperatures. High attenuation and medium-high flocculation. Fermentation range of 57-70°F.
Munton and Fison Ale (Munton and Fison)
An all purpose ale yeast selected for a long shelf life. A vigorous starter, with neutral flavors. Medium attenuation and high flocculation. Fermentation range of 64-70°F.
Windsor Ale (Lallemand)
Produces a full bodied, fruity English ale, but suitable for wheat beers also, including hefe-weizen. Attenuation and flocculation are medium-low. Fermentation range of 64-70°F.
Whitbread Ale (Yeast Lab)
An excellent pale ale yeast with a smooth crisp flavor and fruity aroma. Medium attenuation and high flocculation. Fermentation range of 65-70¡F.
Safale S-04 (DCL Yeast)
A well-known commercial English ale yeast selected for its vigorous character and high flocculation. This yeast is recommended for a large range of ale styles and is especially well adapted to cask-conditioned ales.
Recommended temperature range of 64-75°F.
Saflager S-23 (DCL Yeast)
This lager strain is used by several European commercial breweries. This yeast develops soft estery notes at the recommended temperature range of 48-59°F and more ale-like characteristics at warmer temperatures. From what I have read, I am speculating that this is a Kolsch or Alt-type yeast. This strain of yeast will produce a lager character at 54°F, and homebrewers have reported good results with this yeast. Given the recommended fermentation temperature range, these yeasts may not respond well to lagering (extended secondary fermentation at low temperatures) as described in Chapter 10, and probably should be maintained at 54°F for the duration of the time in the fermenter, approximately 2-3 weeks. I have not used this yeast myself and cannot say for certain.