Stuck fermentation, more yeast?

Question

I have a 2.5-2.75 gallon batch of Amber beer. I brewed it using the biab method. It's been in primary for about 2 weeks. 5 days ago the hydrometer reading was 1.030 and 3 days later it was 1.030. The OG 1.060 was and read after the wort was cooled in the kettle all night.

Mash temperature was 152 and cooled to about room temperature before adding yeast. Fermentation is done at room temperature which varies 65 and 80 around 70 average.

fermentables
5.5 Lb American pale 2 row
2 lb Crystal 40

yeast:
Safale 05 ⅔ packet of yeast (.32 oz) dry Added about ¾ teaspoon of yeast Energizer

1. first question: should I add more yeast to restart the fermentation or is it done?
2. second question: Can I add the remaining 1/3 packet of us-05 yeast that's been sitting on my counter for 2 weeks? is it dead or unsanitary?

Answer 1

2lbs of crystal is likely the reason for the high FG. Pull 500ml and add the rest of the yeast to that. Keep it warm (75F or more), loosely covered and shake it/swirl it for a few days. See if the gravity changes. If it does you might be able to ferment the main batch a bit more. If not then you know you are at terminal gravity.

Answer 2

From what I read about it it seems your mash temperature has been too low on average.

You will end up with primarily maltose which isn't your yeast's favorite food, ergo, your ferment will be partial and your end product will likely taste sweet.

Answer 3

1I believe the fermentation is done. 2 don't add that yeast, it's dead. Not one of your questions but letting your wort cool overnight is not a good idea.