Sure you can! But don’t just build your stash like that. It depends on your milk and baby’s preference. Some breast milk has a high amount of lipase. The longer milk is kept at room temperature or even in the refrigerator before being frozen, the more lipase activity it will have. Some babies are okay with that taste some are not! So before u build a huge stash, you might wanna do a test run on your baby. I used to store my milk like that, then apparently baby don’t like the taste. So I wasted quite a huge amount of bm. And I no longer store my milk that way anymore. I will pump and freeze or fridge.