I see condensation between the walls -- help! September 26, 2017 00:41 Follow Because the glass is handblown, imperfections, while rare, are possible. Please contact us with photos of your glassware and we'll help you get it sorted out. Related articles What makes Fellow's glassware different? What makes Joey Mugs so special? Fellow's Product Warranties How do I use Stagg [X] Dripper? I have additional questions, how do I contact Fellow?