I brew half batches (2.5 gallons) and I aerate with pure O2 using a wand with a 2 micron sintered stone. I have been modeling my aeration after the process used in the Yeast Book. The book says 60 seconds of O2 @ 1 L/M with a .5 micron stone delivers a little over 9 PPM O2. Since I do half batches I use about half that time, around 30-45 seconds @ 1 L/M. I’ve been trying to search info about the different stones and found that the .5 micron is said to produce bubbles with a greater surface area.
Should I be aerating LONGER with the 2 micron stone to achieve the same PPM?
I think the opposite is true. If greater surface area meant more oxygen dissolved then we wouldn’t use a stone at all - we’d just stick a hose in and let really big bubbles do their thing.
I’m pretty sure you’re OK doing what you are doing.
That would be true if only one bubble came out of each. But that one big bubble coming out of the end of a hose becomes lots and lots of tiny bubbles out of a stone. Estimate the outside surface area of an egg white, then froth it into a meringue. Which one is bigger?
Lusk, the difference between .5 and 2 micron stones for what we are doing is really nothing to worry about.
Yeah I guess I didn’t state it too clearly this morning. I was just waking up. You are right and I agree - what I was trying to say is that there is a greater surface area with many tiny bubbles than few big ones. So a 2 micron stone would do better than a 5 micron stone which does better than a hose stuck in the wort.
Yup yup. And .5 even better. Mine is a 2 and I think it’s just fine.