Yeast question.

How important is it to get the specific yeast strain asked for in a recipe? For example I'm trying to do a Brown Ale and they are asking for 013 London Ale yeast, can I use another yeast with similar characteristics and be ok?

Yeast can be interchanged to a degree. In your case a good substitute would be one that has a maltier profile. A good British ale yeast will be fine. It's kind of nice trying different yeasts in the same recipe to note some of the differences.

You'd probably be fine with Safale-04, which is a good and cheap dried yeast strain.

Well, from what I understand from listening to the Jamil show, is that the yeast strain flexability depends heavily on the style. Like a saison for example, can only be made with a specific saison yeast strain, where more run of the mill styles like stouts and pale ales can use a variety of the more neutral yeast strains.

So I guess it has to do with how yeast oriented the style you are trying to make is. Things like belgians, and wheat beers would be much more yeast specific than brown ales and stouts.

That's what I have learned from the master.

html has some good points.

some yeast strains are 'less specific'. others are very attuned to a style. Like hefeweizen yeast...its not very flocculent, and easily produces esters and phenols to provide the cloves and bananas one expects in a hefe.

if you used a non-hefe strain...well then you won't have a german hefe on your hands...it might by a crystalweizen, or an american wheat.

it just depends.