So tired of brides wanting tastings

I do not build the time and or expense of tastings into our pricing. Until now I've been charging $150 for a private tasting and allowing brides to apply that toward the final invoice if they book us which basically makes the tasting free. It seems like most all brides anymore want and expect to have a tasting. So starting now we are implementing a "Service Fee" of 10% of the final invoice of all special events. We have never charged a mandatory gratuity or service fee in the past and will still charge the tasting fee that gets applied to the deposit of the event when booked, but the new 10% service fee is simply to cover the cost of supplies and time involved with a tasting. How do you all handle this? I think of 14 large weddings we have this year I've done 13 tastings.