I have 3 gallons of starter wort that I did not get to use 2 months ago. These are in gallon size glass jars and have been keep cold. If I boil the starter wort again for 15-20 minutes would it be safe to use to make an actual yeast starter with? Normally I would have used this starter wort right away but life gets in the way of brewing at times and I would hate to throw out all of this wort.