Yeast falls asleep in the morning

I'm making a Sierra Nevada clone kit. I broke the batch into halve and did one batch already a few months ago and am doing the second batch now.

The first time I used some Wyeast yeast that came with the kit. Now, the second time I'm using some Safale dry yeast.

Both times I notice that when I wake up in the morning around 8am or so that there is no bubbles in the airlock. I then shake the fermentor around making bubbles and within 30minutes the bubbles go again.

My initial thought was that the yeast use up most of the oxygen at night, then in the morning when I shake it, it wakes up.

Another thought is that the temperature change is messing up the yeast. During the daytime, it is 82F and at night I set it to 77F.

Does anyone have any thoughts on this? I've seen videos the recommend aerating initially but haven't seen any mentioned after this. I've been doing this every morning and sometimes throughout the day.

My only thought is to keep it under 70F if at all possible. The bubbles may just be CO2 that you're displacing when you shake it. Keeping it under 70 will help you greatly with minimizing off flavors in your fermentation.

Yeah don't do that. You're potentially aerating your beer which may lead to oxidation. Yeast only use oxygen in the early reproduction phase which only lasts a few hours before they start active fermentation. There may be some cases where the yeast will benefit from additional oxygen during fermentation, but not with a low gravity pale ale. If you're fermenting in the high 70's or low 80's the beer may already be done fermenting due to the high temps. Don't worry about the airlock. Give it a week or two and then check the gravity for 3 days to make sure its done. The biggest issue you have at this point is your uncontrolled ferm temps. You may have been lucky so far, but fermenting that hot is going to get you a big bucket of paint thinner eventually. Research fermentation chambers or swamp coolers to control your temps and quit pickin at your beer.

That is not a huge temp swing but yeast really don't like their temp going up and down. Stabilize it in a water bath, the mass of the water bath will keep temps from fluctuating so much and you can use ice if needed.

Thanks for the replies. I'll try and lower the temperature a bit or do the next batch in winter.

You can use a swamp cooler to keep the temps even.