RDT stands for Ross Droplet Technique, by adding a small amount of water to your dose of coffee before grinding will reduce the overall static and result in less retention in your coffee grinder. Why RDT matters: This method can be achieved by using a cup of water and a spoon, simply use the back of a spoon to dip into the water and then stir this wet spoon through your dose of coffee. However many people prefer using these spray bottles as they are closed off and don't risk spilling, they are refillable and dispense the perfect amount of water every time. These spray bottles in particular and made from Aluminium and coated in a matte black finish to suit all your favourite brewing equipment. The 50ml capacity may seem small but with around 0.1ml of liquid exiting every spray you will only be refilling your spray bottle after every 500 sprays. You can even use this RDT bottle as an espresso spray bottle. We wrote an entire blog post article on RDT and how it effects your coffee extraction, you can read it here. Can I use RDT for my coffee grinder? It is important to note that you should double check that your grinder is using burrs that are coated and suitable to withstand small amounts of water otherwise you run the risk of rusting your burrs or causing damage to your grinder. The Comandante MK3, MK4 and C60 grinders are suitable to use this technique. So is the Timemore C3s Coffee Hand Grinder. What water should I use? Regular tap water is more than fine to use in the RDT spray bottle however feel free to also use distilled water if you have it available. This RDT bottle can fit around 50ml of water, working out to be hundreds of sprays in each fill. RDT Bottle Features: Aluminium coated matte black finish Plastic pump nozzle + clear cap 50ml Capacity Reusable, simply unscrew cap and refill with water. NEW and Improved Finish: As of August 2025 our RDT bottles have a thicker coating on the exterior, this new and improved finish results in less fingerprints showing and a deeper matte finish! Our product photos have been updated to show this. Included: 1 x RDT Reusable Metal Spray Bottle - Matte Black