Ovaltine Beer - Day 5

Same as before-23 spb (seconds per bubble). This fermentation seems a good deal slower than 5 gallon beers. I wonder if its because the yeast isn't healthy enough, or because of the size of the batch. If I had to guess, I'd go with the latter. It makes sense to me that a smaller batch = less yeast = less CO2 expelled = slower bubbling. Any thoughts?