I am brewing a stout and using Safale US-05. Here in middle Georgia the weather is already plenty warm so I'm using a water bath to keep my wort at a stable temperature. I pitched this yeast at a temp of 60°F and planned to let the temp gradually grow 1-2 degrees per day until primary was finished. I'm on my fourth day of fermentation. Things seemed to be still going well until I checked my wort temp this morning and it was 69°F.
I was worried about the temperature rising too much while at work, so I chucked a frozen gallon jug in the water bath to neutralize the yeast activity, but I came home on my lunch break to find the wort temp at around 62°F. Obviously, I'm worried about the yeasties going down for a nap prematurely.
I'm curious how resilient is Safale US-05 to temperature drops. I know some yeast strains can handle it, but 7 degrees feels like a lot to me. OG was 1.076 and fermentation didn't reach high krausen until yesterday morning.
If my fears are realized and fermentation stalls, should I raise the temp to 75°F and try to stir them up or keep the temp at 70°F and stir them up? What are my options?