I've never been a huge fan of drinking out of jars or cans: I'm more of a flute or goblet girl.
BUT when you're in the most beautifully decorated barn, in the middle of the Suffolk country side, the sun is out and your niece has just got married ..... drinking out of jam, coffee, mayo ANY kind of jar you can imagine, seems entirely appropriate. What a happy, happy day. Congratulations Claire and Charlie. #ccwedding2018