I usually do about 10-14 prints at 11x14 with 2 liters of Ilford Multigrade with no issues. From start to finish is maybe 5 hours. I start with water that's about 68-70. It might cool off some, but not much. If you post the batch code or send it to Simon Galley (he's Ilford's face here), he might be able to tell you how old it is. If the bottle was still sealed, though, I wouldn't think it would go off that fast.