I always use a crockpot to make canna-oil, set on low, for 7-12 hours. Never tried it with butter though. Me and the woman are happy with brownies, canola is cheaper than butter, and that's what the brownie recipes ask for, sooo...I use oil. Butter is probably more flexible though, for baking a variety of things. If you think an ounce is a lot, you wouldn't even wanna see how much I use to make 48 fluid ounces of oil, which is good for 11 pans of brownies. Lasts for months though.