INTRODUCTION

Making great coffee consistently relies on working to a recipe. The following recipe covers variables that need to be in balance to deliver sweetness, balance and complexity. Correctly extracted, high quality coffees like Mastermind from Clark St Coffee, present beautifully as black and with milk.

Mastermind

DOSE: 22g
TOTAL BREW TIME: 30 secs
BEVERAGE WEIGHT: 52g

Wallflower

DOSE: 22g
TOTAL BREW TIME: 30 secs
BEVERAGE WEIGHT: 52g

DOSE

Dose refers to the dry weight of ground coffee in the portafilter basket. We work with 22g VST Precision cut baskets. In these baskets a 22g dose provides enough coffee to split espresso shots into 8oz take away cups but not too much to be over powering in an in-house latte or flat white.

Use scales accurate to 0.1g like the Acaia or OHaus portafilter scales. For the home barista pocket scales with a dosing cup work too.

Keep your dose consistent. Don’t increase or decrease the dose to change the total brew time. Altering the dose will dramatically affect the extraction having a negative effect on the balance of sweetness, body and flavour complexity.

TOTAL BREW TIME

Total brew time is measured from the moment the brew button is pressed. It is directly affected by changes in dose and grind. Total Brew Time can also be understood as the contact time water has with the coffee. We use 30 seconds as our target. This provides enough contact time to develop the sweetness, body and complexity of flavour. The shot needs enough time to fully extract the coffee whilst not over or under extracting. This time remains consistent as we change other variables.

BEVERAGE WEIGHT

Beverage Weight will be a new one to many of you. It is also sometimes known as Weight Out or Yield but should not be confused with Extraction Yield which is a percentage of coffee extracted and a term relevant when working with refractometry and measuring Total Dissolved Solids (TDS).

Traditionally we have measured espresso by volume; 30ml single espresso / 60ml double espresso. But measuring by volume proves to be an inaccurate way to assess an extraction. It can be difficult to assess 30ml visually in a shot glass. The volatility of crema and the lack of precision of the shot glasses themselves introduce variation. A seemingly small change like an extra 10 ml in a double shot extraction is an additional 16.6% volume making a significant change to how the coffee tastes.

Additionally 30ml is not usually the optimum espresso extraction. Often a slightly longer extraction is required to bring out the sweetness, complexity and balance from a coffee.

It is more accurate to weigh the espresso in the cup. Our target beverage weight of a double espresso of Mastermind is 52g. Use scales accurate to 0.1g like the waterproof Acaia Lunar. The home barista can use a set of pocket scales too.

Once you program the volumetrics on your machine to a beverage weight of 52g you will find it far more consistent than free-pouring shots.

GRIND SIZE

This is the important one. By eliminating changes to the previous variables, the only one left is grind size. Frequent adjustment will be needed throughout the day.

A finer grind exposes more surface area, which allows for a greater extraction. This will also slow the pour as there is greater resistance. Too finer grind will cause over extraction and make the coffee flat and bitter.

A coarser grind exposes less surface area and will decrease the rate of extraction. Since there is less resistance the pour will be quicker. Too coarse and the coffee will be sour due to under extraction and lack sweetness.

CONCLUSION

There are many variables at work when it comes to espresso extraction. Understanding their effects empowers you as the barista to accurately trouble shoot. Keeping the variables of dose, total brew time and yield consistent leaves you with one variable to change in order to meet the recipe – grind size.

The value in serving a consistent and correctly extracted coffee shouldn’t be underestimated. Combine this with great customer service and you are on your way to creating satisfied return customers.