Started with and IPA 1.074. Waited 4 weeks looked like everything finished up and i kegged it. I double checked the gravity and it was only 1.040. Was looking for 1.017 ish. I originally pitched 2 packets of WLP001. Its been fermenting in my basement at a 64-66 degrees. It was a little low but everything seemed like it was working away. Right now i have it in a keg conditioning in the same temp. Should i leave it or try to ferment it out. Never had this issue, but i usually don't use WLP yeast either. Any advice??