Leftover Coffee & Peanut Shell Bitters

Believe it or not, there are so many things you can do with your leftover brewed coffee.And I’m not talking about composting or making face masks.

I’m talking about making aromatic bitters with them!

I know, many baristas and coffee lovers out there find it sinful to rebrew their leftover grounds, but that’s not exactly what we’ll be doing here.

We will be simply infusing whatever flavor is left from the grounds into a spirit to make super concentrated bitters.

Like a chef would use spices in his or her cooking, a bartender uses bitters in his or her cocktails.

Bitters add depth, complexity, extra flavor, and yes…bitterness!

They seem to always be that ingredient that we reach for when we find that something’s missing in our drink.

Needless to say, they play a very important role in our industry, which is why today I’m going to show you how to make some using leftovers that you would regularly find behind the bar or in your home.

Take note that anyone can make this recipe as long as they have a couple of common household items.

IMPORTANT: THIS RECIPE CONTAINS PEANUT SHELLS!! If you are only allergic to peanuts you can substitute them with another type of nut. Otherwise, don’t use any nuts at all and make regular Leftover Coffee Bitters.


(This recipe will make just 50ml of bitters)

  • 2 tablespoons of Leftover Coffee
  • 2 tablespoons of Peanut Shells (hand crushed)
  • 1 thick peel of Grapefruit Skin and Pith
  • 5 black Peppercorns
  • a few pieces of Ceylon Cinnamon (don’t use the other types of cinnamon)
  • pinch of Salt
  • 75ml of Anejo Rum or Dark Rum
  • 1 tablespoon of Muscovado Sugar or Molasses or Brown Sugar



  • Cheesecloth Filter or Fine Strainer
  • Microwave
  • Jar or Microwavable Glass Container
  • Empty Bitters Bottle

The Technique of Microwaving

These bitters are relatively simple to make.

We will be combining all of our ingredients together in a jar. Instead of letting them sit for weeks to infuse, we will zap everything in a microwave to extract all the flavor possible without losing any alcohol from evaporation.

This technique may seem strange, but it’s actually used quite a lot by one of the best bartenders and bar owners in the world, Mr. Lyan!

Microwaving works great in drinks because it infuses booze at a fast rate in a safe way. Just make sure that you are using a glass jar with a plastic lid. Avoid metal at all costs!

Part I:
Caramelizing your Sugar

The first thing to do is to caramelize your sugar.

The reason why you want to caramelize your sugar is to add extra flavor, color, and sweetness to balance the bitterness of the other ingredients.

I’m using Muscovado sugar which reminds me of chocolate chip cookie dough and works excellently with dark rum. I also suggest you to use Molasses as a substitute, but if you don’t have either, go with your regular brown sugar.

Place 1Tbs of the Sugar in a pan with just a drizzle of water. Put everything on high heat and continuously stir. You don’t want the melted sugar to stick completely to the bottom of the pan and burn.

Once the mixture creates very LARGE BUBBLES like in the photo on the last photo, transfer everything into your Infusion Jar and be quick about it!

Your syrup will harden and be sticky almost immediately so you want to do this fast.

Part II:
Combine Other Ingredients

just follow the list of ingredients to put into the Jar with caramelized sugar.

Below I have re-listed the ingredients describing the purpose of each one for the final infusion. I’ve also come up with a substitute for each ingredient in case you don’t have these specific ones!

2 Tablespoons of Already Brewed Coffee

Leftover brewed coffee works great in this recipe since there’s lots of flavor in them and considerably less caffeine…meaning that these bitters won’t keep you awake!

Yes, these coffee grounds have already been brewed once before, but zapping them in the microwave with alcohol will get every last bit out.

It will also extract some lovely bitter flavors!

2 Tablespoons of Leftover Peanut Shells

Make sure to crush your peanut shells by hand before you throw them in the mix. Like in this photo.

Peanut shells have the same flavor and aroma as peanuts. They are edible, but not enticing because of their texture. Leftover Peanut Shells give nutty notes to the bitters and work in harmony with coffee.

If you don’t have peanut shells lying around your house use another type of crushed nut.

1 Thick Grapefruit Peel

Make sure that you don’t peel your grapefruit using a peeler, but rather peel it using your hands. You want to grab plenty of Pith (that’s the white part) as possible because that’s what’s going to give your Bitters their bitterness! The outer peel will instead give some notes of fruitiness in the infusion. Feel free to use Orange or Lemon instead.

5 Black Peppercorns

These are to give a spicy note to the drink and some extra zing. They will uplift the other flavors as well.

A few pinches of Ceylon Cinnamon

By a few pinches, I mean extremely little. The smaller the bitter. We don’t want to accidentally make cinnamon bitters, but we need just the right amount to give that same uplift and spice that the peppercorns give.

A Pinch of Salt

Salt will enhance all of the flavors in our infusion. I’m using Himalayan Salt.

75ml of Anejo or Dark Rum

I’m using Havana Club Especial as my spirit of choice, although Dark Rum will work really well too. The reason being that all the flavors mentioned above will work in harmony with these two spirits.

Part III:
Microwave It

Once everything is together, close your jar, give it a quick mix, and pop it in the microwave.

Blast it at 600 Watts for 45 seconds.

Let rest for 10 seconds.

Then blast it a second time for another 45 seconds.

The infusion should be bubbling vigorously in the jar so just let it cool down.

You absolutely do not want to open it up, otherwise, you will lose a lot of your alcohol from evaporation. Come back after a couple of hours until it’s completely cooled down to room temperature.

Part IV:
Strain & Bottle It

Open up the jar and strain it using a cheesecloth or coffee filter. You can even use one sheet of paper towels.

Let it sit drip by drip and near the end, squeeze out any liquid left out of the solids.

You will have lost some liquid from the coffee and peanut shells soaking the booze up, but it’ll be well worth it.

Now you have your super tasty Coffee & Peanut Shell flavored Bitters! Have a taste!

The main flavor will obviously be coffee followed by the bitter and fruity notes of the grapefruit peel, and finally a lingering aftertaste of nuttiness coming from the peanut shells.

If your concoction is too bitter or not bitter enough you can always add or remove the grapefruit pith from the equation.

Try it in Manhattans, Old Fashioneds, or even just in your plain Soda Water.

Here is an amazing recipe that highlights this timeless classic cocktail.

Featured Cocktail:
Brown Derby


Traditionally made with Bourbon, This cocktail works excellently well with Scotch because of its perfect harmony with the bitters.

The aftertaste of the coffee and peanuts sit and linger in the background.

Rather than using a lemon peel as a garnish, a lemon infusion is sprayed onto the drink.

This helps us to avoid wasting commonly discarded lemon peels. 

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