Thermometers for Barista's from Coffee Spares Direct. Your milk being at the correct temperatures makes the perfect coffee. We sell thermometers that clip into your milk jug and also the label type of thermometer that sticks on the outside of the jug. To help make the perfect espresso the Coffee Sensor can be installed onto your E61 brew head to give you an accurate reading from start to finish in your coffee extraction. Buy your milk and E61 group heads thermometers from Coffee Spares Direct.