If you've ever tried nicotine gum, you'll know that nicotine itself is quite peppery. I'd love to know how to neutralize the pepper taste completely (other than diluting it to a super low nic density). However, adding a drop or 2 of sweetener such as ethyl maltol or sucralose helps quite a bit. (I put in 2 drops per 5 mL). You may find you need to add more flavor concentrate when you use a sweetener, so just experiment, but it's worth it.