Best RDT Spray Bottle For Espresso & Coffee Beans

 Last Updated November 5, 2023

So you've heard the hype about the Ross Droplet Technique (RDT) and want to test it out yourself. But finding a good-sized spray bottle actually take a bit of work. You'll find a lot of places only sell bottles in bulk or larger sizes, when all you need is single small spray bottle. In this post I've done the hard work and listed three of the best RDT espresso spray bottles for making coffee.

RDT Spray Bottle

My RDT spray bottle

Best RDT Spray Bottles

Below I've listed three of the my favorite Ross Droplet Technique bottles. They're all the right size and well designed. 

RDT Spray Bottle Black

The black RDT bottle is the staple for any coffee set up. It produces a nice mist to coat your beans and holds 50ml of water. The bottle is also made of a hardened glass for a premium feel.

RDT Spray Bottle For Coffee

This is the RDT spray bottle I use at home. I like it as it's small, only 10ml in volume. So it doesn't  take up much space. I even took the container out of the casing to make it even smaller. 

RDT Fine Mist Spray Bottle

If you do want a few bottles on hand as a back up, this pack of 3 Amber bottles are a great option. I love the color of these and they produce a nice spray. 

Now that you know where to get a good fine mist bottle, keep reading on how to use the Ross Droplet Technique.

What is the Ross Droplet Technique (RDT)?

The Ross Droplet Technique, aka "RDT", is barista slang for spraying a small mist of water (droplets) over your coffee beans before you grind them. It's named after the David Ross who's credited with the idea. The benefit of the RDT is seen when your single dose your coffee.

When you grind you beans, it greats static electricity within the grinder that causes a portion of the grinds to get stuck within the grinder. A small spritz of water is the solution to this issue. The water helps get rid of the static so that your beans don't get stuck within the grinder on their way out. 

So if you grind 18 grams of coffee, you'll get 18 grams of coffee out. 

Below you can see the difference when using an RDT spray. On the left I used no water, but on the right I did a small spray. You'll see the most benefit if you use a coffee grinder that has a high retention of coffee without anti-static devices.

Grams retained in the grinder

Without RDT: the grinder held a gram of coffee.

No retention of grinds with RDTv

With RDT: No retention of grinds with RDT spray.

How to use a RDT Spray Bottle

It's very simple to use a RDT spray bottle. All you need to do is do a single spritz of water over your coffee beans in a container, give them a light shake to coat the beans, then put them in your grinder. That's it! You can see me going through the process below.

1. Weigh out your coffee beans

The first step is to weigh your coffee beans with a good coffee scale. I use 18 grams of coffee for my espresso recipe.

2. RDT your beans!

WDT spray onto coffee beans

One spray is enough!

The next step is to wet your beans with your RDT bottle. I like to do 1 spray of light mist water. You don't want to over soak the beans as then you'll get the grinds clumping together - which defeats the purpose of the technique.

3. Give your beans a shake!

WDT shake wet coffee beans

Shake those water droplets!

Give your beans a light shake so they are evenly coated with the water droplets.

4. Grind your beans

Single Dose of Coffee

Next up grind your beans and enjoy the benefit of reduced static and low to no grind retention. The RDT technique only works if you’re single dose your coffee. If you use a full hopper like in a cafe, then there is no point doing it.

5. Weight your ground beans

No retention of grinds with RDTv

No retention thanks to RDT!

18 grams in and 18 grams out! Make sure you measure your ground beans again to make sure all the coffee came out of your grinder.

6. Enjoy you coffee

Coffee with Ross Droplet Technique

Now enjoy your coffee with made with repeatable results. The RDT method can be seen as a bit "over the top", however at its core it is used to help you make repeatable, great tasting coffee. That's a win in my books.

What makes a good RDT Mist Bottle?

There's really only three things you need to look out for when buying a RDT bottle:

  • Size: You want a spray bottle that's comapct and that holds no more than 60ml of water. The reason for this size cap is that you want it to be easily accessible on your coffee bar.
  • Build quality: You want a bottle that's well made. Most bottles are made from glass, plastic, or aluminium. Price dictates the build material, but they all do the same thing well - spray water.
  • Spray mist: You want the water droplets to come out in a light mist. All of the bottles I've recommended in this post do this. This helps evenly coat the beans.
Ross Droplet Technique

My spray bottle I use at home.


And there we have it, I hope you have found a good bottle for your coffee bar and have learnt how to use the Ross Droplet Technique. Below is my top recommendation as I think it appeals to most people. If you have any questions, feel free to leave a comment.

RDT Spray Bottle Black

This black RDT tool is the staple design for any coffee set up. It produces a nice mist to coat your beans and holds 50ml of water. The bottle is also made of a hardened glass for a premium feel.

About The Author 

Ivan Bez

Ivan is the founder of Latte Art Guide and a barista with 10 years of experience. He loves coffee and aims to help people improve their coffee making skills.

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