Yes, and no. There is good quality and bad quality. Fleishmann's is good but if it lingers too long in the store, it can be a bit less good. Red Star is good, as is SAF. There are a few other smaller ones that are good.

How much do you bake? ADY lasts very well in the freezer if it's kept air tight and moisture free. I assume it's the same for IDY, which is just ground up ADY. I have a little jar that originally held pistacchio butter and refill it every couple of months from the frozen Red Star. If you're baking bread at least weekly, it's worth getting the one pound bags and freezing. If you're baking bread regularly, but less often, the Fleischmann's jar is a good choice, kept in the fridge. It also comes in a one pound bag, but that's not common to find at the grocery.

Because of the environmental factors, bulk in the fridge is better, but if you prefer packets, you can put them in the fridge too. That's really wehre the better lies--the environment you store it in, and the exposures during shipping and supply chain storage.

If you're happy with Fleischmann's, there's no need to change. Basically, yeast is yeast. Sourdough (naturally captured yeast) is a different strain from commercial. It's all pretty resiliant, with the most vulnerability to heat and moisture.

Sorry for babbling. I can't seem to muster even an attempt at brevity.

I usually bake one loaf of bread a week, nothing fancy. I did switch to the jar and have been keeping it in the fridge; it's more economical and easier to use than the packets.

So, then, you're doing just fine. If you start a new jar and it seems weak or otherwise not what you're used to, return it to the store for an exchange. Back in the days of cake yeast, which was moist. so much more delicate than dry, my mother occasionally had a bad batch, and she thought Fleischmann's was far superior. I changed to pound bags of Red Star duing the Pandemic when that was what I could get.

None of the "daily" bread I bake (baking is more or less weekly) is very fussy over quantities, but my mother's challah is very picky and really wants yeast packet measures. That's just 2 1/4 tsp. x batch size,, and easy enough, but I adore my little yeast spoon from KA that measures one packet worth.

https://shop.kingarthurbaking.com/items/yeast-measuring-spoon

^^ Now that's a clever little utensil. :0)

So I was thinking SAF and Red Star are the same thing so I looked it up. Same parent company, and per google their ADY and instant yeasts are identical, with SAF packaged in bulk for commerical and Red Star smaller packaging for home. There are different variants that do differ from each other.

But what got interesting was when I asked about Fleischmann’s. Different company altogether, and their yeast is different from the SAF/RS. Now I’m not claiming knowledge just quoting Gemini: Fleischmann’s products tend to have a more traditional yeasty smell, vs a cleaner, sweeter SAF/RS. And Fleischmann’s instant yeast is made to go straight to shaping, allowing a first rise can have undesirable results.

Interesting. What I was thinking was whether the bread will rise. ;)

Haha yeah as long as the yeast is alive I guess!

Funny story - Last weekend my wife called a neighborhood restaurant to order a pizza for takeout. They told her that for some reason the dough isn’t rising, and asked her to call back in an hour to see where they’re at. We went somewhere else but I’m so curious what happened. I’ve got a jar in the freezer, it’s covid years old but still works, thought about dropping it off for them half as a joke.

All kinds of things can happen to the yeast. It could be killed before it was used, like if someone left it out near the oven. They could have used too hot water. They could have dumped acid on it. Etc. Or they could have forgotten to put it in (I thought you put it in! I told you to do it!) Usually, restaurants don't proof the yeast, which makes it harder to catch issues.

Re live yeast, some poorer yeast is actually weak and might do for brioche but balk at a heeavy whole wheat. As in they don't butp enough to make it puff up. Of course, there's always the stickiness and stretchiness of the flour to contend with, as well, when looking for a good rise. Since your post, I've been thinking about getting a jar of Fleischmann's to see if I catch a difference. I've found the Red Star to be very reliable and it doesn't need proofing (though it does want to warm up--I usually do a preferment anyway, so it can go in cold). But I'm coming to the end of the bag, and now that I know Fleischmann's also comes in pound bags, I'll test them and see if I like one better.