Low Krausen and Low Airlock activity after 4 days

Hey whats up guys,

I brewed an english bitter on friday with yeast i had collected from my previous batch (about a week before). OG hit 1.045 but i still have very low airlock activity and krausen is not as high as i expected. Could it be that i underpitched? Should I add more yeast? Or should I just wait?
Oh its about 75 degrees in here right now and i’m not controlling temperature

Did you take a gravity reading to make sure it isn’t done already?  Also as has been posted here many times, if you ferment in a bucket, you may have a lid that didn’t seal properly.

But I would first check the gravity.  Always do that when in doubt.

Ok i’m actually kinda shocked haha. Gravity hit 1.014. Sorry for the dumb post, thought taking a reading would be useless.

At that temp, a 1.045 will be finished very quickly.

Don’t worry. Have a homebrew…

In my experience, harvested yeast that is very fresh will complete in a very short time.  With a 75 degree ferment, you may have a serious ester and possible fusel situation, but good luck and enjoy your bitter!