Add more yeast or not?

Hi there, about a week ago I did a batch of extract brew using a recipe I've had success with before using S-33 yeast. For about the first 12 hours it bubbled away quite happily, but since a pretty cold night it has barely moved. (Where I live in Queensland, Australia, a cold night is 55 F). I've checked for leaks and there are none. Is it just fermenting really slowly or should I put in some more yeast.

Also, if I do put in more yeast and it doesn't need it, will that affect the taste badly?

Sorry if this is in the wrong forum...

Dave

What's the current SG? In order to know if fermentation has stalled, it's important to know the SG.

SG is 1.016. Unfortunately I didn't take an initial reading, but I'm aiming for about 1.012.

Am I risking ruining the brew by re-adding yeast?

I would try to warm it up to the high 60's maybe even around 70 and see it it drops any more. Most of my brews stop in the range of 1.014 -1.018.

I don't think I would do anything to drop it a further .004. To me that is not a significant amount.

Agreed on warming and rousting the yeast. Wait a three or four days and check the sg. If its still 1.016, then I think you're done and can bottle or keg.

Great, thanks for your help. I'll check again, and bottle if it looks good. I think in future I'll check SG at the start to save me this trouble. Probably should have been already, but I've finally learnt my lesson.