To make coffee-infused oil for hair growth, you'll need to heat coffee and oil together. The provided YouTube video "DIY Coffee Oil For Hair Growth" explains that to infuse the oil with coffee, you will need to let it cook on low heat for about half an hour (0:19-2:34). You can scale the recipe up, maintaining the same ingredient ratio.
While the specific ratio of coffee to oil isn't given, and other methods may exist, this information provides a basic approach.
