How To Dial In A Coffee Grinder

September 21, 2021 3 min read

Weighing espresso into a portafilter at Rumble Coffee Roasters

So you’ve done it. You’ve spent the money and bought yourself a shiny new coffee grinder (maybe even a beautiful Breville Smart Grinder). Now, how do you get the most out of it?

We always say that the best possible thing you can do to improve your coffee is to grind it right before brewing (a little piece of every coffee roaster dies every time that we have to grind a bag of coffee for someone). Always grind fresh, never grind off a day's worth of coffee and leave it sitting as it stales and loses its flavour and punch within minutes

EK grinder

 

  1. Start with freshly roasted coffee beans. We recommend using a nice, consistent espresso blend, something like our Haymaker, Shadow Boxer or Streetfighter blends.

 

  1. Fill your hopper with your coffee beans of choice and grind a small amount to purge any old coffee that remains. Make sure your fresh coffee is coming out before pulling your first shot.

 

  1. You need your espresso machine warmed up and ready to go. And you need some scales. Some people balk at the thought of weighing their coffee but we have to say, that the biggest improvement we’ve seen in specialty coffee in the last twenty years isn’t in high-tech grinders and exotic new coffee varietals (though they’re great too) it’s in the simple act of weighing. 

Rumble three pack main card

 

If you weigh the ground coffee going in and the brewed coffee going out and time how long it takes, then we guarantee you can make delicious coffee. 

 

The golden ratio for brewing good espresso is 1:2. That is, for every gram of ground coffee you use, you get two grams of brewed coffee on the other side.

 

The basic recipe we aim for is 20g in, to 40g out, in a time of 30 seconds. This is our starting point in the quest to brewing the perfect espresso.

 

In a cafe setting and at the roastery, we tweak this recipe all the time for certain coffees. But it’s where we always start and you can’t go too wrong following this recipe. If your home machine has smaller baskets, say 18g, then use 18g in, to 36g out.

 

If you want to see our different recipes for different coffees, then look at our Rumble Recipes account on Instagram.

 

  1. Fill your portafilter with coffee (20g in this case), tamp firmly so it’s flat and start the shot. 

  2. Stop when you reach 40g of coffee out. Check the time.

 

Was it too fast? Then adjust the grind size finer. Smaller particles will slow the water down as it passes through the coffee bed.

Too slow? Then you need to grind coarser. Larger particles will let the water find its way quicker.

Acaia Coffee Scales

 

  1. Adjust the grinder. They are all different, so you’ll need to learn how much of a grind adjustment to make. Changing the grind size is easier if you do it while running the grinder. Make minor adjustments each time.

  2. Purge a small amount of coffee through the chute to clear the old grinds away.

  3. Tamp and pull another shot. Is it close to the recipe? If yes, then taste the coffee. If not, then make another adjustment. (Don’t already drink black coffee? Then this is your chance to learn.)

  4. Does it taste great? If so, then you have the coffee dialled in and ready to go. Get another shot ready and make your drink of choice.

  5. Not there? This is when you can adjust the recipe by pulling a longer or shorter shot or look at adjusting the temperature of your machine.

  6. Getting the perfect shot takes time and practice, but is well worth the journey.

Joseph Molloy
Joseph Molloy


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