Looking around at various calculators, it seems that a dry yeast packet has about the same viable cells as a brand new liquid pack, and way more than an average age liquid pack.
Are dry yeast starters common, or do most people just make a slurry while re-hydrating and pitch right in? This is for a 1.065 OG beer.
I never do starters with typical dry yeast. Just properly rehydrate them and you are good to go. One pack of dry yeast is enough for a 1.065 OG. I have pitched one pack of dry yeast (US-05) up to a 1.075 OG and been just fine with minimal lag time and good attenuation.
An 11.5 g packet of dry yeast at 2 billion cells per gram is actually more like 2-3x as much as a pack/vial, and just about what you’d want for 5 gal of 1.065 ale. Rehydrate and you’re good to go.
From what I have heard through the years, a starter with dry yeast is actually detrimental. Something to do with the process and timing in which the yeast is prepared. Mark may be able to confirm
I do not think making starters with dry yeast is very common because (i) the cell count per sachet is quite high, (ii) the cost per sachet is low and (iii) dry yeast is propagated in such a way that for most beers it is not necessary to add additional oxygen to the wort (a property you will lose if you make a starter).
Its not detrimental per say. It does use all the reserves that the yeast come packaged with, making it not a simple pitch with no O2 or nutrients anymore. If you make a stater, its not biggie , you then just treat it like a normal yeast starter from then on out. Nutrient, O2 and the like.