Here's my starter routine. I use the term routine loosely since I've only done it once. I make the starter Sun am. Put it in the fridge Mon and and brew Tues (my day off). Last time I did it, it was a rainy day so I had to do a partial boil inside because the starter was ready. If this happens again, and I opt to put off my brew day for a week, is there something I can do with the starter so it's usable in 1 week or do I have to toss it and start over?