January 7, 2016

Weighing Espresso Shots in Service: Should You Do It?


Picture the scene: a bustling café, a queue of takeaways to the door, and a full rail of checks. It might sound stressful but for the barista this is standard practice. You’re weighing espresso shots, steaming your milk, and pouring coffee – it’s all just part of the daily grind.

But for specialty coffee baristas, no matter how busy it gets, there’s one more thing to consider: consistency. In fact, in the specialty coffee world, consistency is key. It’s how we know that each shot is as delicious as the last. And this requires you to practice weighing espresso shots.

Spanish Version: Pesar el Espresso Durante el Servicio: ¿Locura o Esencial?

So how do we guarantee consistency? First, we dial in a recipe first thing in the morning before the door opens. This involves experimenting with weighing and timing your shots to find the ‘sweet spot’ where your espresso tastes its best. The catch is that once you’ve found it, you’ll want to hit it each and every time. And you do this by weighing every single shot.

Impossible? Unrealistic? Too scientific? No – just essential if you consider your service specialty.

Specialty cafés commonly pride themselves on their high-quality coffee and the wonderful flavours their baristas can extract from it. Whether it’s a hint of sweetness or aroma, our coffees often surprise and delight with their unique flavour profiles.

However, because coffee is organic and the process of making espresso is manual, the results and factors determining them (humidity, temperature, air pressure, and human error) – are changeable.

This is the barista’s greatest challenge and can make or break a café’s reputation – quality control and consistency.

So what do we do about it? Let’s weigh it up…

v60 setup

Setup for V60 brew.  Scales are a necessity,  so why not have the same standards for espresso?

How to Solve Espresso Inconsistency By Weighing Espresso Shots

An obvious and reliable way to eliminate or minimise the impact of unpredictable factors when making coffee is weighing espresso shots. This process usually involves adding steps into your workflow, which usually go something like this:

1) Place your empty portafilter on a scale and tare it

2) Grind your coffee into your portafilter and reweigh it, ensuring you have the desired dose in your basket (here you may need to discard or add some coffee)

3) Distribute the coffee in your basket (usually with a light tap on the side of it) and tamp

4) Carefully insert your portafilter into your machine’s grouphead

5) Place your cup on a scale, tare it, place it under your portafilter and hit brew

Some say that this kind of technical approach to preparing espresso is reductive, as if it saps the joy or artistic element out of it. While this might be true to some extent, it’s also true that even a difference of ±2g of coffee can massively affect extraction time and, as of such, flavour. Goodbye consistency.

Now, you might think that adding lots of steps to the already seriously long list of things you’re paying attention to during a busy service is a bad idea. Yet the bottom line is that doing so, and hitting your recipe every time, keeps the quality of the coffee you’re sending out high and consistent. The trick is quick, calm execution – and the experienced high-volume barista will do this with seemingly miraculous, effortless cool.

Within the barista community the consensus seems to be that so long as you have a smart system in place, weighing your shots is in fact quicker – and more consistent – than not weighing them (more on this later).

weighing espresso shot

How to keep your dose consistent: a scale is the best friend of specialty coffee.

Weighing Espresso Shots: The Step-by-Step Instructions

There are a few key factors that will hugely impact how well you’re weighing espresso shots – and therefore how delicious it tastes.

First of all, you need to decide on your dry dose, that is, how many grams of ground coffee you’re going to put into your portafilter’s basket. Then you need to synchronise a further two factors: the coarseness of your grind and the time it takes to pull your shot.

Most specialty cafes will be running one or more ‘on demand’ grinders. This is generally because doing so is a good step towards achieving espresso consistency. You can set them to grind a certain amount of coffee at a fixed grind size in a set number of seconds.

However, not even the best grinders out there can guarantee 100% consistency in their dosing. They can become clogged with espresso ‘fines’, and some grinds can be lost or spilled before they enter the basket. This is why the reweighing stage after grinding is essential: you need to check your dry dose.

Now you need to distribute the grinds so that the bed of coffee is perfectly flat. This will ensure you achieve evenness of extraction (and a balanced flavour). So with your cup on your scale, placed under your portafilter you can pull your shot.

The best way to achieve consistent results here is by using a volumetric coffee machine. These contain flow meters that push a set volume of water through the espresso puck so that provided the dose is consistent, the resulting shot will be the same volume every time.

But how do you determine the dose going in, the yield coming out, and the time it takes for it to do so (which will be affected by the grind size), along with whether these parameters have achieved the best possible extraction for your coffee?

You experiment and create an espresso recipe…

espresso shot being pulled

Consistency in your shots – you’ll need a recipe! Credit: Flickr, Jayson Leow.

SEE ALSO: How To Pull A God Shot At Home

How to Create an Espresso Recipe

The aim here is to determine a solid recipe for your espresso that is really going to showcase that particular coffee’s flavour profile. This way you’ll be able to recreate it every time you make a drink and know that your coffee tastes the best it can.

Begin with setting a brewing ratio. The most desirable tastes of espresso are usually achieved using a ratio of 1:1.5 to 1:2.5. This means that if you use 18 g of espresso, you want to achieve 27 g of espresso in your cup, using a 1:1.5 brewing ratio. Try weighing 18 g of your espresso and pull a shot.

weighing espresso shots

Start with scales, your portafilter, and 18g of espresso.

empty portafilter on scale
espresso in portafilter

Position the portafilter on the scales, tare, and put your 18g of espresso into the basket.

How long was the extraction? What weight is the yield? If your shot was too short, the espresso will be under extracted. This often results in salty or sour-tasting espresso. The longer the shot and the more water you’re pushing through your espresso, the more you’re extracting from your coffee. But be careful – it’s very easy to over shoot, and this will give you over-extracted espresso. This often tastes bitter, won’t have much flavour, and will have no lasting finish. So you want to find the golden middle: the sweet spot where the extraction is optimum.

Proceed with caution, always adjusting only one parameter at a time. If you’re under extracting, try tightening up your grind; this will give you a longer shot. If it’s over, then you might need to loosen it, making your grind coarser and your shot shorter.

Just make sure you give yourself enough time. This can sometimes be a frustrating process as the variables can differ hugely from coffee to coffee, but be patient – It will only result in your coffee tasting consistently fantastic.

Weighing Shots: Theory And Practice

So you have an on demand grinder, a volumetric machine that automatically stops the extraction, and your coffee dialled in with your trusted recipe. The next thing you need to guarantee you always hit your recipe is a good set of scales. Without one you just can’t be sure how accurately you’re keeping your brew ratios.

So how can we effectively put all this theory into practice?

It’s a question of workflow efficiency. Timothy Sweet of Base Espresso in Broadbeach, Australia is one such barista that believes a workflow involving weighed shots will always be faster and more consistent than one without – so long as two key stages are executed: keeping your scale in place and pre-grinding your next shot while your first one is extracting.

It’s hard to believe that adding stages to workflow can actually reduce time, so we put it to the test and challenged Timothy.

I timed myself pulling three shots without weighing them, in the way I would do in a normally paced working situation. I needed 1:02 from grinding the first shot to the end of the last extraction. Timothy did the same but weighed his shots and pre-ground the next shot during extraction. He completed his flow in 56 seconds. 6 seconds may sound insignificant, but multiply this by the number of shots you might pull in a day during a busy, high-volume service (this might be anywhere from 400-1000) – plus a bit of inevitable barista fatigue – and that extra time is going to pile up.

But more important is the consistency of all those shots. If you nail down weighing your shots within your workflow, you’re simply going to be making better coffee consistently.

So you see, if you consider your service specialty there really is no excuse for not weighing your shots. It’s pretty close to a sure-fire way of ensuring you’re getting the best from your coffee  – and the best for your customers. Not only this but you’re extending the longer processes of speciality coffee production: you’re paying respect to the roasters and farmers that also used all available methods to produce the best coffee possible.

Looking forward, it seems that consistency is a top priority for the specialty coffee industry. German manufacturer Mahlkönig is currently developing a grind-by-weight technology which will automatically sense the weight of the portafilter, grind, and stop when the dose when the desired weight is reached. It’s expected that you’ll be able to add this technology to your existing grinder, making your espresso dose even more consistent.

Until then, grab your scales, experiment and keep searching for that perfect recipe.

Feature Photo Credit: @coffeecircle

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