I made a double batch of my homemade granola and this morning I notice that the top of the granola was all fuzzy. I keep it in an airtight container. Does any one know what would cause it?
Toss the granola and sterilize or recycle the jar. Molds are from the fungi family and it is likely the spores either survived the baking process (you need heat to kill but too much burns the granola) or your batch got infected afterwards (the useful hands comment, or an opened or unclean container).
If doubling up the recipe gave less room on the baking sheets to spread out the batch that might be part of the problem. Make smaller batches and consume faster. If you are using a recipe and making substitutions the new items you are adding might be creating the problem. Many of the food preservation techniques for fighting bacteria (low pH, moisture, temperature and high salt or sugar) don't work for fighting molds.