I've been buying 4oz bottles ( a little over 100ml ) from amazon and so far everything is good. I used this peppermint oil :

https://www.amazon.com/gp/product/B00OEIBJRW/

My peppermint soap won't be done curing until this weekend, but it has a good scent! My CP recipe was around 45% olive oil, 29% coconut oil, 22% palm oil, and 2% shea butter.