# The dangers of coffee roasting



## NickR

As I regularly commute into London by bike, last year I became increasingly worried by the reports in the media regarding air quality. So much so that I purchased one of these

Link:*http://amzn.eu/26AJAKh

I have now taken hundreds of readings. My general impression regarding London air quality is that the reports are vastly exaggerated.

WHO guidelines for exposure are

PM2.5 25ug/ 24 hour mean

PM10 50ug/ 24 hour mean

If there is absolutely no wind, then number can get high. The highest I have measured on my road was: -

PM 2.5 = 53.3

PM 10 = 70.2

However, the slightest breeze seems bring the figures of even the busiest road down below the WHO guidelines. Recently there were roadwork's near my house resulting 3 rows of stationary traffic outside my house for most of the day. There was a slight breeze.

PM 2.5 = 3.7

PM 10 = 6.1

These are typical figures for busy London Roads on an average day with a very slight breeze.

Yesterday I measure the air quality in my kitchen before roasting

PM 2.5 = 3.0

PM 10 = 6.3

I use a Gene Café with a 3-metre duct out of the window. This is old, but has no obvious leaks. At no point was there visible smoke in the kitchen.

Throughout the roast the figure climbed reaching a peak of

PM 2.5 = 270

PM 10 = 248

In the garden the reading reached over 1000 for both PM 2.5 and PM10

Given that the particulates are the result of combustion; I think it can be assumed that this is highly dangerous.

Forget wearing a mask on a bike, wear a mask when you next roast coffee.


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## ZappyAd

I think I saw someone on TV (possibly Quentin Wilson) saying that motorized vehicles only account for 10-15% of toxic particulates in the air and that something like 80% comes from the commercial and domestic burning of carbon. I suppose he mainly meant coal and wood but maybe they need a subsection for coffee!


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## DavecUK

I would keep quiet about this Nick or Mr Kahn will want to charge you £40 every time you roast!


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## MildredM

That is really interesting. I have been interested in air quality and airborn contaminates for a while. It would be good to get some decent/factual info on bean roasting air smoke. I also wonder what safeguards are made in roasteries apart from suitable air extraction.

I would love to test a variety of situations to compare - the smoke from a cigarette in a room, say.


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## hotmetal

80% of the pollution in Westminster is from hot air being generated by our glorious leaders and wannabes. ULEZ really stands for Unlikely to Lower Excise Zone. Apparently though the air around duck islands is fit to breathe if you don't mind the agricultural aroma of BS!


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## u2jewel

I heard that you can take in caffeine through breathing whilst roasting. It's that true?

I guess ventilation and exhaust are common sense things when it comes to roasting.

Every time I go back home, or go to a developed country (as opposed to developing, like Vietnam where I'm currently stationed), the very first thing I always realise when stepping off the plane is how clean and fresh the air is. Here, it is gradually getting better, and maybe not as bad as Beijing, but some days, your eyes sting just being outside. Just like after a swim in an over-chlorinated swimming pool.

My kids school has a dedicated website showing real time pollution level, and outdoor activity/P. E. is always cancelled if it goes above UN recommendations.


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## espressotechno

? Just fit a filter on your roaster flue to catch the bigger particles ?


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## NickR

espressotechno said:


> ? Just fit a filter on your roaster flue to catch the bigger particles ?


I'm thinking of putting a small extractor fan on the outside end of the duct to ensure that the smoke is pulled out of the Gene


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## u2jewel

NickR said:


> I'm thinking of putting a small extractor fan on the outside end of the duct to ensure that the smoke is pulled out of the Gene


I don't have this roaster so only speculating, but if you change the air flow speed of the exhaust, couldn't that potentially pull more air through the whole system, thus affecting roast temp stability?


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## Rob1

Genesis preformed tests on the roaster shortly after reports roasters were at risk of 'popcorn lung' from diacetyl released from the bean during grinding and roasting (mainly grinding).

Genesis' tests indicated measurable levels to be within safety limits even when measured directly over the exhaust during first crack (though my memory may not be 100% and you should google this to fact check).

How long until readings returned to normal? Have you tested the air quality in your kitchen while cooking or around your coffee machine/grinder?


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## dsc

I'm not so sure the reading are definitely exaggerated, yes a breeze will move polluted air from around the sensor and move fresh air in, but if you imagine a nose instead of the sensor you'll most likely just breath in the polluted air even if its followed by fresh air.

I'd say it looks like it' simply a momentary measurement. Also is there a way to calibrate this device or compare the readings to something proven?

T.


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## jeebsy

Rubens Gardelli has a pretty serious looking gas mask type thing we wears when he roasts.


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## CoffeeRat

jeebsy said:


> Rubens Gardelli has a pretty serious looking gas mask type thing we wears when he roasts.


 normally drum roasters pull air from the room to outside (and the only time when operator is in danger of inhaling some gases incl. diacetyl is only when door is just open and roasted coffee is falling into the cooling table but haven't reach it yet) maybe his self-made one works opposite


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## dsc

Stick a massive exhaust system which is triggered when the door is open and roasted coffee is making it's way to the cooling table and you should be fine. Gas masks are probably fine if you have no exhaust fans fitted at all, at which point the whole arrangement is not legal anyway :/

T.


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## shadow745

I roast on my balcony that gets a healthy north wind whipping around the corner, so smoke/particulates are almost never an issue. No way would I roast indoors though.


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## Hasi

Interesting stuff...

Just the other day I cut a piece of OSB in shape to fit in the window frame next to my roasting place downstairs. Later this week, it will receive aluminium ducting as well as a small (and weak) in-line fan to pull the fumes directly from my Quest's exhaust and out of the garage







not worried about steam in dry phase, but the rather bad smoke during development and cooling. Next thing I'm looking into is a cheap hand-held anemometre to check if the arrangement does anything to the internal airflow. Not too sure, though, where to hold it to for usable readings









I've seen people install powerful kitchen hoods in their workshops but they get so loud at full speed you would have a hard time hearing FC. Despite a rather big investment, you might not arrive at 100% fume removal...


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