Dead yeast is good yeast?

Question

I just came across this:

Different strains of Saccharomyces cerevisiae produce different proportions of carbon dioxide and alcohol. Baker's yeast is a blend of several strains of Saccharomyces cerevisiae chosen for their flavor and ability to make carbon dioxide, which causes bread to rise. Brewer's yeast is made of strains chosen for their alcohol-producing ability and tends to have a bitter flavor. Brewer's yeast is considered an inactive yeast while baker's yeast is an active yeast. In an active yeast the yeast cells are still alive, whereas they are killed in the process of making inactive yeasts, like brewer's yeast.

https://www.livestrong.com/article/418496-what-is-the-difference-between-brewers-yeast-bakers-yeast/

Which I found surprising, thinking yeast was useless (for anything) if not alive, and having read of rehydrating and proofing with malt extract and checking for signs of life, for example:

If it's not showing signs of life (churning, foaming) after a half hour, your yeast may be too old or dead. Unfortunately, this can be a common problem with dry yeast packets, [...] Have a third packet available as back-up.

http://howtobrew.com/book/section-1/yeast/preparing-yeast-and-yeast-starters

Is the first article just plain wrong (certainly it seems much less of an authority on brewing) - or is there some subtlety here that makes both quotes sort of correct but not quite telling all?

Answer 1

I am calling bullshit on the first article. Does this make any sense to you?

"Brewer's yeast is used to brew homemade wines and beers, while baker's yeast makes bread rise. You can't brew alcohol with baker's yeast and you can't leaven bread with brewer's yeast"

This is completely wrong. They are both are saccharomyces cerevisiae and do essentially the same thing. People use both all the time. Use baker's yeast to make beer and use brewers yeast to make bread. I have made pizza dough from beer yeast so I know it works just fine.

Have these different strains been optimized for a specific purpose? Sure and baker's yeast makes a mediocre beer, but they are all alive and active. I think the confusion is coming from "brewers" yeast that is used for a nutritional supplement which I think is baked to kill the yeast and leave the hulls behind. Also, there is a difference between dried and fresh, which also seems to confused the author. Otherwise, all yeast you buy for the purpose of brewing and making bread are considered active.