Gene Cafe - Large Chaff Collector

Gene Café - Large Chaff Collector
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Roasting coffee in my kitchen with the Gene Café was becoming a smelly, smokey and at times, a frustrating experience. My routine prior to roasting coffee would include: positioning a desk fan to direct air flow towards an open kitchen window; placing the Gene as near to the open window as possible; forgetting to turn off an over zealous smoke alarm and finally ensuring my that my expelair is switched on to its highest extraction mode.

Typically, once the Gene Café was filled with ‘greens’ and the roaster started, despite the above measures my kitchen would soon start to fill with a familiar ‘grassy’ like smell associated with roasting coffee. Prior to my first home roasting venture, I’d imagined an intensely welcoming aromatic experience, whilst roasting coffee, but the aroma I got resembled more like the burning of damp straw. This isn’t a particularly unpleasant smell for some people, but I quickly got sick of it and its ability to cling to clothing and linger for days afterwards through-out my flat. …I can not imagine this stuff being lung friendly either! Usually, around 8 minutes into a roast, my smoke alarm would start screaming, hence an awful shrill cry of a reminder for forgetting a pre-roast task. Once it’s switched off I’d then quickly return to my kitchen to join forces with my desk fan and expelair; arm myself with in tin tray and listen closely for ‘second crack’ during the roasting process. ‘Second crack’, signalling that the end roasting cycle imminent – I do like a dark roast - at this point, armed with my tin tray, I’d now be attempting to chase out as much smoke as possible, out through the nearest open window by waving my tray up and down at it and generally attacking it like I imagined a brave Samurai warrior, using his skills and sword to protect his family from attacking evil assassins – you get the picture – anyhow, back to my kitchen, after a few minutes of smoke fighting, the cooling cycle on the Gene would be well underway and ceased the producing smoke.

Before purchasing the large (Gene Café) chaff collector, I’d considered taking my Gene to my parent’s house to roast so I could use their large but very cold garage, but the distance factor alone would render this a major inconvenience. Costing me £35 the Large chaff collector is not cheap – by now, however, I imagine that most of you will have become hardened to such price tags attached to coffee related stuff – it’s made of the same heat resistant plastic as the standard chaff collector included with the Gene Café roasting unit. The large chaff collector connects to the gene in exactly the same way as the standard chaff collector. Being much bigger it can handle a few roasts at a time without needing to be emptied, however, I tend to empty after each roast as I tend to think that an empty chaff collector will aid smoke extraction, but when I’ve forgotten to do so on numerous occasions I haven’t noticed any problems.

The design of this unit enables smoke to be extracted up towards a cooker-hood or similar extraction point in your home and placed near an open window it will do a far, far better job blowing smoke outside than the standard chaff collector. To ensure an almost smoke/odour free zone, when roasting in my kitchen, I purchased a 3 meter length of aluminium corrugated semi-flexible ducting to extend the exhaust capabilities on the chaff collector. This particular ducting is flexible so it can be easily positioned and offers far greater heat resistance than plastic ducting used on tumble driers etc. I purposely chose ducting with the same diameter of the chaff collector’s exit hose 80mm (3inches) as I found this fits well and, more importantly, works perfectly. So well in fact, that I really believe that the large chaff collector ought to be sold with a length of the said ducting as standard as it really completes the large chaff collector as a very effective extraction unit.


The corrugated (aluminium) semi-flexible ducting that I’m using was purchased from for £7.40 + P&P (3m length + 80mm diameter). This ducting is available also at most large DIY stores and should around £5 - £7 per 3m length. You may find that the most commonly available size for this type of ducting has diameter of 100mm (4 inches), but this will not make too much difference and will do the job well.

NB. The ducting I have been using does get quite hot during a roasting session so be mindful of all areas of contact. Ducting tape wrapped around points of contact would eliminate the potential for burning your hands or scorch marks forming on windows etc.


My own setup is now simplicity itself as I just place one end of the ducting over the chaff collector’s exit hose and the other end wedged pointing upwards & outwards between the opening in the window. The plumes of dark smoke I see exiting outside via the duct, just prior to and at the start of the Gene’s cooling cycle, is quite a shocking sight, especially with the knowledge that most of that smoke used to invited into my home, clothes and lungs during every roast. …Despite my best efforts with the tin, desk fan and OAP expelair.

Finally, I’d like to add that I’m extremely pleased with my purchase. The money spent on the large chaff collector and the £7 (approx.) for the length of ducting has, in my experience, been money very well spent. I can honestly say that around 98% of the smoke is now directed outside, leaving my kitchen smoke free. Setting up the Gene Cafe for a roasting session has now well and truly lost its chore status; my roasting equipment is now not only a doddle to set-up and dismantle, but has saved my roaster from being banished to a cold harsh garage. I feel I have renewed my passion for ‘home roasting’ and now look forward to the roasting process with almost the same enthusiasm as sampling a ‘shot’ from the fruits of my labour.