Using a Gene Cafe as a sample coffee roaster - Sidewalk Coffee Company

Using a Gene Cafe as a sample coffee roaster

What is a Gene Cafe Roaster?

A Gene Cafe roaster is a small 270g (max) coffee roaster that uses hot air and an off centre rotating glass 'drum' to evenly roast coffee.

It's really easy to use and relatively cheap.  

We've been using these machines for a few years now and I thought I would write a few words on what we think the pros and cons are of using the Gene Cafe as a sample roaster.

If you already have a Gene Cafe or another small batch roaster then check out our green bean coffee store here: Sidewalk Coffee Green Coffee Bean Store



The Gene Cafe is a plug and play product.  It requires minimal training and maintenance.  You can roast coffee in around 14 minutes with a full drum, and less than 12 with a lighter load.

Your second roast will be quicker because the residual heat knocks about a minute off the total roast time.


There are two controls.  One of which doubles up as an on/off switch.

Time - how long you want the coffee to roast for

Heat - maximum temperature

You can adjust both throughout the roast


It's real easy to clean. Just remove the chaff collector after every roast or two.

We've had a couple of fires which although were contained by the chaff collector it did damage the plastic a bit!

Always clean it out!  Chaff is really flammable.




The simplicity of the controls also have  down side.

There's no airflow control.   And although there's a heat setting it takes a while to get there so you're pounding your coffee with heat for 10 or so minutes.


It's really tempting to overfill the drum.  Don't.  Coffee expands quite a bit when it's roasting so what looks like a small load at the start will expand and fill the drum towards the end of the roast.  This can create a number of issues but an uneven roast is most likely to cause you a problem.  Fire is another one - it's a real risk.  Don't assume you'll get away with it.

With smaller beans you can load around 270g and get away with it.  However it's best to go with 225g and enjoy a shorter roast time with more evenly roasted coffee.


It's not loud, but it's loud enough to mask the sound of first crack.  Fortunately the Gene Cafe has a glass drum so you can watch the coffee roast.  You can just about hear 1st crack but you'll most likely miss it so learn to spot the colour and volume changes that occur towards the end of the roast and you'll be fine.

Cooling phase

The Gene Cafe takes a while to cool down.  So the 12 or so minute roast needs about 5 minutes to cool off.  This is too long as the coffee is still cooking after the timer has gone off.

To mitigate against this, you need to stop the coffee roasting about one stage lighter than you require.   The cooling cycle will 'coast' through the next roast level and you should end up with the coffee you want!

Note we use a 220/240v machine.  I hear that 110/120v machines have longer roast times.



The Gene Cafe is a great little coffee roaster and yes we use it occasionally for sample roasts.

We don't use the Gene Cafe for our commercial or domestic sales though.

We'll be publishing a video soon on tips and tricks so keep and eye on our YouTube channel for updates.


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