Everything you need to know about Brix readings for coffee

Aidan Gant
June 23, 2022
Everything you need to know about Brix readings for coffee

The specialty coffee movement is typically characterised by the pursuit of high-quality coffee and innovative approaches to its improvement. 

An additional characteristic of the sector is the careful consideration of coffee origins and processing methods. The key to this is observable and quantifiable data, and Brix readings are an important metric in all stages of a coffee’s journey from bean to cup. 

“Brix” is a unit of measurement commonly used by food technologists to measure the amount of sugar dissolved in water. In the coffee industry, the Brix percentage may indicate the typical strength of a coffee. 

These measurements can provide both roasters and baristas valuable insight into the solubility of a roast, determine how equipment is set up, and may even help roasters achieve the ideal roast.

That said, Brix readings can be difficult to understand and easy to confuse with other similar readings, such as Total Dissolved Solids (TDS). 

Read on to find out more about Brix readings for coffee and how they benefit coffee farmers and roasters. 

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close up image of teaspoon full of sugar over a cappuccino in a white cermic cup on saucer.

What is a Brix reading?

Brix readings have been a standard form of measurement across a number of industries for many years.

Essentially, they represent the sugar content of a ‌liquid. They have proved useful for the wine industry, honey producers, food scientists, and baristas, to name a few. 

The measurements are recorded in degrees Brix, or °Bx. One degree Brix represents one gram of sucrose per 100 grams of solution. 

This method of measurement and standardisation of sugar solution strength was first discovered in the early 19th century. 

While a few different scales were set simultaneously, the most widely used was discovered and named after German mathematician and engineer Adolf Brix. 

The Brix scale is now the agreed standard for the coffee industry, and readings are calculated using a refractometer.

A refractometer is a device that measures the angle of refraction, or the change in direction of a beam of light as it passes through a liquid. This changes depending on the sugar content of the solution being tested, allowing users to take a precise Brix reading.

It is important to note the sugar content of green coffee affects the aromatics and flavour profile of a coffee. Notably, sugar content can be influenced by a coffee’s cultivation and processing methods.

A Brix reading can also be converted into an approximate Total Dissolved Solids (TDS) reading for brewed coffee. However, this may not be the most reliable way of doing this, as Brix measurements are better for maintaining a precise product specification at an industrial level.

Alternatively, TDS is best used to determine hot coffee extraction calibrations in a commercial setting.

Optical Brix refractometers are relatively affordable, while digital refractometers used by coffee professionals average around $700. That said, they are an invaluable tool in calculating TDS and extraction percentages in brewed coffee.

Close up image of ripe red coffee cherries in a wide, flat straw basket, being sorted by hand.

Why are Brix readings important?

Along the coffee supply chain, Brix readings are most important with green coffee. 

They are taken at origin to determine the ripeness of coffee cherries. This is done by squeezing a drop of its juice into a handheld refractometer. 

This is the one of the most reliable methods of detecting readiness in the cherries, and can be further reinforced by visual observations such as colour. 

The reported average range for green coffee is 15 to 25 degrees Brix. However, farmers catering for the specialty sector may have a tighter range for their optimal harvest. In dry seasons, this figure may rise into the 30s.

At every stage of the coffee supply chain, it is vital to have a repeatable and dependable set of data to help with quality control and consistency.

In addition to using Brix readings during a harvest, coffee farmers can use them to make informed decisions about processing methods and storage solutions.

For example, coffee destined for a natural process, where a developed fruity sweetness is desirable, will benefit from a longer ripening period on the plant – or Brix reading of over 25 degrees. 

It is important to note that Brix readings should always be taken at room temperature. As the scale is calibrated to be 100% accurate at precisely 20ºC, any deviance in temperature may result in a less accurate reading.

This is due to the fact that relative density fluctuates according to temperature, which affects the manner in which light refracts on a liquid.

Image of roaster inspecting a batch of freshly roasted coffee beans under a ring lamp.

How do Brix readings benefit roasters?

While it is essential to know the exact sugar content of green coffee at origin, Brix readings can also provide roasters with useful information. 

The caramelisation and Maillard reactions that occur in the pre-crack development phase of roasting rely on the sugar content of the green bean.

Therefore, it is vital for roasters to understand the compound structure of the coffee they are working with. Knowing this can help them adjust the roast profile according to sugar content, maximising the potential of the beans.

If a roaster knows the coffee has a high Brix reading, they can encourage a complexity of sweetness. This can be done by adjusting the development time between the beans yellowing and the first crack. 

VST Lab coffee refractometers are the industry standard as they allow for a greater range of readings and can accurately adjust results according to temperature. Paired with the proprietary mobile phone app, they are a valuable tool for evaluation and quality control.

That said, they are costly, and more affordable optical refractometers can be just as effective. 

In less economically developed nations across the bean belt, affordable access to this data is essential. Monitoring the sugar content of green coffee through Brix readings can be useful at origin. 

It can be an indicator of not only harvest readiness but whether producers need to adapt their farming methods to produce higher-quality coffees.

Image of Caucasian pouring water into plastic V60 with filter paper and coffee grounds, with white multilayer kraft paper coffee pouch in background.

For roasters, Brix readings can help determine the quality of green coffee and provide insight as to whether it is being stored correctly. Furthermore, it is particularly useful information when dialling in a roast profile, as it can help roasters reduce the amount of waste due to mistakes. 

At MTPak Coffee, our dedicated Education Centre can help producers, roasters, and baristas learn more about the technical analysis of coffee. It is also a handy, free resource to help you stay on top of industry trends.

Our goal is to support your coffee business, whether it be through skills development or by supplying you with sustainable coffee packaging. We offer a range of sustainable packaging options that can reflect the distinct roast profiles, flavours, and characteristics of a broad variety of specialty coffees.

Choose from a variety of features, including degassing valves and resealable zippers, to ensure that once you have achieved your desired roast profile, you can perfectly preserve the freshness of your coffee.

For more information on sustainable coffee packaging, contact our team.

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