When using dry yeast - how do you proof it?

Okay, I'm using the Homemade Soda Rootbeer and Pop book (or whatever Steven Creswell's book is called). Had a question on the yeast. You are supposed to put 1/8 teaspoon of dry yeast in a 1/4 cup lukewarm water and let it sit for a few minutes.

How do you know if the yeast is good? Should it dissolve? If I want to make sure it's good - should I put a little sugar in to give the yeast something to start on? Or just take it as a matter of faith that the yeast is good?

(have rootbeer that has been working a little over three days. Just a little carbonation - not much - so want to make sure I get it right)

Dry yeast needs to re-hydrated in plain, warm water, that's all. Unless it has been open for a few weeks, you can assume it's good.

Dry yeast when properly packaged can have quite a shelf life. Trust the dates on the package, they are your friend.

No proofing here. Just rehydrating in a little warm water. The point of rehydrating is to give it something to just rehydrate the cells without having them suck up a bunch of sugar. When they're rehydrating, they can't control how much of what crosses their cell walls and suddenly sucking up a bunch of sugars can kill many of them. Just rehydrate in plain water and then pitch.

Thanks for the info!

Next yeast question. When making aone gallon batch of soda, how much yeast should you use if you want high carbonation / a frothy head on your root beer?

I used 1/8 of a teaspoon in a 1/4 cup of lukewarm water. I read some recipes calling for 1/8 teaspoon, others calling for 1/4 in the same basic recipe, and recipes at Mother Earth magazine calling for 1/2 teaspoon for one gallon mixes.

If you go with a small amount (1/8 teaspoon), does it give the same carbonation as 1/4 teaspoon, just takes a little longer? Would 1/2 teaspoon have a heavier yeast taste? How do you make that balance between taste and carbonation (individual taste, so I guess it would be a matter of what I preferred).

I haven't even been re-hydrating lately, and I'll be damned if I can tell a difference. Beer's usually in the basement late-afternoon and fermenting away happily first thing in the morning, which is good enough for me.

As long as you have an adequate amount, more yeast won't give you more carbonation. It's the amount of sugar that is available for the yeast to eat that determines the amount of carbonation.

Thanks. I have rootbeer to refrigerate in the morning (if it lasts that long! Three 12 ounce bottles went to frosty mugs, one 12 ounce bottle was popped in the freezer for a rootbeer slush. I "tested" one last night, then today some have been shared).

Have cream soda just started this afternoon. Hoping to wait until it has carbonation. Have more sugar in the cream soda than was in the rootbeer.

Next goofy question. When I add the dry yeast to the lukewarm water, then add that to the rootbeer mix - what temperature should the rootbeer mix be? What temperature range is lukewarm?

60's or so. Room temp is fine for pitching. Generally, you want the yeast, the water you rehydrate the yeast in and the liquid you pitch it in to be around the same temp to avoid thermal shock to the yeast. But there's leeway. It ain't rocket surgery, ya know.

Okay - that might explain the slow carbonation. My lukewarm was pretty toasty. I am getting some carbonation, but it is slow. Just learning things for the next batch.

ok. I read several posts on soda, but I'm dubious about the use of yeast for pressurized. even using a small amount of yeast, he should not multiply and end up consuming all the sugar by making the bottle explode?

It worked just fine. Took a little time. You just have to move the rootbeer to the refrigerator once carbonated to slow down the yeast. I'm sure you could pasteurize it if you wanted to - but I've never had fresh, homemade cold rootbeer sit in the fridge long enough to cause any problems.