So, since I am still getting a feel for my new equipment, I brewed the same recipe two nights ago and last night, only difference was my sparging technique.
Two nights ago I tried fly sparging through a strainer and got a pretty low mash efficiency, approx 60%. I was aiming for a final volume of 1.25 gal with an original gravity of 1.071. I ended up with approx 1.35 gal (played with the stove a little much when boiling) and an original gravity of 1.050. I used a Wyeast british ale smack pack which i started before i started to brew and was inflated by the time I pitched. Since these were small batches I pitched half the pack and poured the other half in a sanitized mason jar topped with aluminum foil and left it in the fridge ( i know it was exactly half because I actually poured it out into two same sanitized mason jars first to make sure it was split even).
The next night I batch sparged, got a mash efficiency of approx 65% and ended with a final volume of approx 1.11 gal (got a better feel for the stove after last night and managed to keep it at a roaring boil without boiling over so I lost more due to boil off) with an original gravity of 1.066. Then I pitched the leftover yeast.
After 48 hrs since the first batch and 24 hrs since the second, the airlock in my second batch has a healthy amount of activity and the airlock in my first has none. Other than the fermenting bucket and the issues described above, nothing is different between the two.
Now here's my question, if we ignore the possibly of the fermenting bucket lid not sealing, would the lack activity be due to the lower gravity, since there is less sugar and all?
I am still new to brewing but this is the second batch I have made in the 1.050 and neither shows activity although the first did ferment so maybe at that low of a gravity it doesn't show in the airlock?