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Frequently Asked Questions

Read some of our Frequently Asked Questions regarding coffee roasting and coffee in general below. For more information and tips view our coffee roasting blog, or contact us.

What Machine Should I Use to Roast at Home?

At Coffee Roasters, we have a selection of home coffee roasters to make roasting at home simple for everyone from beginners to professionals. Our home coffee roasters are a must have for any coffee lover.

When Was Coffee Discovered?

It is said that coffee was first found and consumed in the 9th century (800 AD) by the Ethiopians. However, the earliest credible evidence of knowledge of the coffee tree appears in the middle of the fifteenth century, in Yemen.

What is "Fair Trade" Coffee?

Fair trade coffee, or equal exchange coffee, refers to when coffee is traded by bypassing the coffee trader, which therefore provides the coffee producer (and buyer), with higher profit margins.

What size roaster do I need?

It depends on the required production output and frequency you want to cover per week initially and into the future. Another factor to consider is the footprint of the equipment verse the space you plan to locate it in. An easy way to work the batch size is to consider the average hourly output. You can usually base this on approximately 3 batches per hour back to back roasting.

So for example with a 5kg batch roaster, you may be able to achieve 15kg of green coffee or app 12kg of roasted coffee (weight loss is app 15%-20% from green to roasted) per hour. You should also consider how often you want to be roasting to complete your weekly production schedule. It is important to consider the time required for other business practices such as administration, sales and marketing and allocate time accordingly.

Can I run a roaster off a gas bottle?

Yes but you must conform to Australian standards for the installation of the gas bottle and gas lines. This must be done by a certified gas fitter and you will need proper sign off and certification. There are certain requirements relating to the placement of the gas bottle that need to be considered. In Australia you are not allowed to operate from a gas bottle that is located inside a premise. Contact your local gas fitter or energy authority when considering LPG or Natural Gas installation.

How much coffee can I roast in a day?

You can roast as much as the batch capacity of the equipment can handle within a certain period. Refer to "What size roaster do I need?" in relation to working out hourly production capacities of equipment.

What is the difference between an electric and gas roaster?

The difference usually refers to the heating source for roasting the coffee. Either that being of gas heating or electric element heating. Both heating methods have advantages and disadvantages but in our experience, you can achieve comparable results with both methods.

Electric heating has its limitation beyond 3kg batch roasters due to the amount of electricity required to produce enough heat making them not cost effective.

Gas heating is more responsive than electric heating but electric heating has an advantage of producing more subtle radiant heat that has a non-aggressive drying effect to the coffee and can produce good results especially if combined with a perforated drum type.

There are different burner types for gas heating that can produce varying levels of conduction and convection in the roasting process. For a comprehensive understanding of roasting thermodynamics, our Coffee Roasting Fundamentals course covers this comprehensively.

Why do I need a sample roaster?

Sample roasters typically are designed for commercial QA analysis of coffee by commercial green coffee brokers and coffee roasting companies. They usually are designed to roast anywhere from 100-200g per batch which is typically the sample size that green coffee brokers will supply to coffee roasting companies for testing.

Trying to roast samples this small in larger commercial roasters is very difficult so it can be an advantage to have a sample roaster to assist in the initial and ongoing testing of green coffee. This also reduces the waste from the testing process whereas if this was to be done in the larger commercial roasters the amount required to roast effectively would be much larger.

What is a roast control system?

A roast control system is an electronic interface that allows the roaster to control the roasting process. This is designed to make the process of roasting coffee easier and more repeatable and usually involves software that maps the process on a computer.

Coffee Roasters Australia has their own in-house developed coffee roasting control platform called Coffee Sweet. This system is available as either a pure datalogging system or a full automation control system where the roaster can be controlled from a computer.

Do I need to test the moisture levels in my coffee?

This is the best practice as the moisture levels in coffee have a direct effect on the roasting process. Green coffee is quite porous and can lose moisture in dry environments as well as absorb moisture in humid environments. The fluctuation in moisture content of stored green coffee has been proven to have a negative effect on acidity levels.

Ideally, a roasting operation should be checking the moisture content in coffee to confirm bought coffee is within an acceptable level of 9-12%. Anything outside these parameters should be rejected. It is also necessary to record moisture levels of the coffee, as it is being stored to ascertain any issues with the storage environment, fluctuations will have an inverse effect on the quality of the coffee over time.

A moisture analyser is also a good quality took for a coffee roaster to use to check before roasting to consider whether the drying effect in the roaster will be faster or slower than the target recipe. The roaster can then make appropriate adjustment to load, gas and fan settings to account for this change. For example, less moisture means the coffee will dry faster than before and the inverse for more moisture.

Do I need an afterburner?

An afterburner is a very effective emission solution that is connected post the coffee roasters chaff cyclone and oxidises the smoke and odour from the resting process by processing at a temperature of usually 500-600 deg.

An emission solution for odour and smoke from the roasting process may be a requirement from your local council or Environmental Protection Agency (EPA). It is best to consult with your local council whether you will require an emission solution for your operation.

Coffee Roasters Australia is a leading manufacturer and supplier of afterburners in Australia and also overseas. We have supplied afterburners to a variety of coffee roasting brands and types and can custom make solutions to suit most applications.

What does a destoner do?

A coffee destoner is designed to separate foreign matter from roasted coffee. Foreign matter such as sticks, stones, metal and other unwanted materials are classified as a defect in coffee and usually introduced into the coffee at the harvesting and processing level. Some of this foreign matter can be detrimental to grinding equipment and can prove costly if grinder blades need to be replaced from damage caused by a stone or piece of metal.

Typically a destoner will sit at the end of the cooling tray of a coffee roaster and will work like a vacuum cleaner when dumping the cooled coffee by sucking up the roasted coffee at a rate slow enough, more dense and different sized objects will remain in a waste tray.

Coffee Roasters Australia is a manufacturer of high-quality coffee destoners with the flexibility to custom design for various applications.