# Severin, Severin, speak so slightly



## Nerdlinger (Jan 10, 2020)

My first attempts at roasting were disappointing. I'm not convinced that the beans even reached first crack though I'm not aware of ever having sampled lighter roasted coffee before, the espresso I made tasted like cereal. I used an unmodded (apart from a whisky carton replacing the plastic scoop lid which is prone to melt) Severin 3751 popper with Brazil Santos. The beans darkened and looked about right after 6 minutes or so but I couldn't distinguish any cracking noises from the rattling beans, I tried switching off a couple of times just for a second but still heard nothing. First attempt (60g) I stopped after 8 minutes, second attempt (100g, see photo) 12 minutes and third time (100g) warmed it up first and kept going for 24 minutes which, from what I have read here and elsewhere is a bit too long.

On that third attempt about a third of the beans popped out of the spout, which might have stopped the temperature rising according to some accounts. Also I read somewhere that it magically starts working after a few attempts, perhaps due to a build up of oils or something maybe increasing the friction to bean movement. Anyway, to counter the bean loss I've inserted a collar made out of a beer can, the chaff should still be able to escape. I shortened the whisky carton and perforated the end (not sure why I did that...) and stuck a jam thermometer in there. I'll give it another try when the current stormy weather blows over enough to be able to open the kitchen window again.

Even before this popper was delivered I was already looking at more elaborate machines. I'm less interested in the better hot air versions, even though Gene Cafe 101 seems to work best of all the home roasters, I really like the look of Bocaboca 250.


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## Hasi (Dec 27, 2017)

what's the wattage of the Severin? and what's your mains voltage?

with a popcorn machine you need to find the right charge weight to make it operate properly.

any chimney of sorts will alter your result, not necessarily for the better - maybe also try with rolled fine wire mesh so that air can escape but chaff and high flying beans get caught 

it'll take a while to figure your popper put, so stick with it!


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## Nerdlinger (Jan 10, 2020)

it's 1200W, 240V.

I just drank espresso from yesterday's second batch and it's not nice but I did finish it. I read an article about resting the roasted beans but it's hard to imagine this batch improving to actually tasting nice.


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## Hasi (Dec 27, 2017)

give it a week to ten days to settle, especially if you've had sour notes in it. Freshly roasted coffee features lots of instable compounds that slowly emit CO2 into the environment. If a molecule somewhere inside a bean dissociates, it'll take a while for carbon dioxide to actually leave its point of origin. As long as it is trapped, it will be compressed to carbonic acid during espresso extraction (CO2+H2O--pressure-->H2CO3).
Crema will be of course be terrific, but fading quickly and tasting pretty sour if a coffee isn't fully rested.

Also, for light and acidic roasts, you can try to increase brew temp by a couple degrees to tame a good bit of their acidity.


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## Hasi (Dec 27, 2017)

PS: 1200W should be good for 80-90g I'd say. Is 240V straight your measured mains voltage? In some areas (and at certain daytimes in some cases), current fluctuations can get you under 230V, costing you 50W of power.


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## CJV8 (Apr 8, 2019)

I was roasting 120g in my Severin, and with cycling on and off roast times were 8 to 9 minutes. I did have an exhaust and a chaff collector (which looked remarkably like some intercooler pipework, silicone hose and Ringtons' ginger biscuit tin....) which raised the temperature quite a bit, hence cycling on and off. But it also didn't fill the kitchen with chaff!

As Hasi says definitely let your beans rest, especially for espresso.

First crack was audible, just takes a few roasts to tune your ear to the sound.

Have a play, with such small batch sizes you can try all sorts of methods and times and not waste too much money.


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## CJV8 (Apr 8, 2019)

I should have also added, when determining the weight of beans to roast (as it'll vary depending on your power supply) you need to make sure the bed of beans is rotating, if it's not then reduce the weight of beans, if it's spinning frantically increase the weight of beans.

A slow rotation at first is fine, as the beans go through the drying phase they lighten so will begin to rotate faster and start bouncing.

No rotation will result in scorched beans and an uneven roast.


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## Nerdlinger (Jan 10, 2020)

The wind dropped enough for another go this morning. I lost fewer beans but still lost a handfull. I did 2 batches of 100g Brazil Santos which my bean dealer roasts lightly, just as well because the highest temperature I measured was 206C after 10 minutes, 205C after 7 minutes, still couldn't discern any cracking and the temperature went no higher. Both times I switched off for a few seconds to adjust the collar or listen out for cracks and the second time I noticed that the temperature dropped a few degrees and didn't look like it would recover, maybe due to bean loss. I forgot to measure the mains voltage but I remember the tone of the popper changed in pitch when I put the kettle on during my first attempts on Wednesday so I can see what you mean there.

Hasi, it did have a sour taste and fantastic crema which dissapated quick. Unfortunately I binned the first batch it tasted so bad but I still have the second and third plus today's 2 so I'll let them rest for another weekish and see if it is more palateable.

CJV8, I like your setup. My chaff collection method has been to roast on the edge of the (wet) sink and point the spout into the sink with a washing up bowl strategically placed to catch overshoots, it works well. So next time I'll use a longer beercan collar so the beans stay in and increase to your 120g. I've run out of Brazil Santos, it will be Colombian next which my dealer roasts medium and dark so I'm really hoping I can get it hotter.


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## Norvin (Sep 10, 2014)

Anybody else get the Velvet Underground reference of the title?


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## lake_m (Feb 4, 2017)

Norvin said:


> Anybody else get the Velvet Underground reference of the title?


 Yes but I couldn't think of how to say it. Venus in furs utterly brilliant.


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## Nerdlinger (Jan 10, 2020)

My mains measured 228V. Bit low maybe.

After resting for a week or so those lightly roasted beans were nicer and I did use them up but I didn't enjoy them anything like as much as my bought-in dark roast espresso.

My latest attempt last Friday finally achieved a high temperature, I stopped at 227 degrees C after 9 minutes using an increased weight of 120g (Colombian Excelso) when it got smoky The longer beercan section helped keep all of the beans in the popper. Thermometer melted a bit. I think I heard some cracking but I certainly didn't hear cracks from each bean, far from it. Tried it this morning, might need more resting but it tastes better than the previous lighter roasted batch. Next time I will go hotter again.

My Venus in Furs earworm has finally gone, weeks after being triggered by coming across the Severin brand name...


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## wan (Oct 19, 2016)

CJV8 said:


> I was roasting 120g in my Severin, and with cycling on and off roast times were 8 to 9 minutes. I did have an exhaust and a chaff collector (which looked remarkably like some intercooler pipework, silicone hose and Ringtons' ginger biscuit tin....) which raised the temperature quite a bit, hence cycling on and off. But it also didn't fill the kitchen with chaff!
> 
> As Hasi says definitely let your beans rest, especially for espresso.
> 
> ...


 could you share with me what pipe size you use? a can tin slightly bigger cannot fit.


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## wan (Oct 19, 2016)

@CJV8 i can see cable with red and blue for what?


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## CJV8 (Apr 8, 2019)

All the pipework is 2" intercooler stuff off the auction site. There's a dull gold piece in the top of the roaster that acts as a reducer, I'll dig it out and photograph the parts for you over the weekend.

The wires poking out were a thermocouple. I was trying to rig up a 12v temp sensor to give the bean temp but the display failed on first use, the replacement they sent out never arrived and shortly after I got myself the Gene so never bothered to get another.


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## CJV8 (Apr 8, 2019)

I'll get photos sorted tomorrow Wan.


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## CJV8 (Apr 8, 2019)

OK, here's a few photos showing my efforts.

The first photo with the glass chamber was my first attempt, we had an old lamp that I took the glass from and for a while it worked well, it contained the chaff and I could still view the roasting beans. However after a while cracks started appearing in the glass so it was immediately binned, the last thing I wanted was pieces of glass getting in among the beans!

The revised model used the same items with the addition of a makeshift collar made from a cut down tin can (coconut milk I think, but other tins are available.... ), and then a piece taken from the same lamp that donated the glass piece cut down to form a reducer to locate the 2" intercooler pipework and silicone hose onto the top of the roaster.

The chaff collector was cobbled together from a biscuit tin with a hinged lid and a vent cut into it with some expanded mesh to retain the chaff (or at least about 90% of it).

It works well enough, but not being able to view the beans as the roast develops was a big downside. As it turned out with the increased temperature generated by the system being more enclosed I had to cycle the Severin on and off to prevent the temperature rising too fast, and those 'off' periods gave me enough time to lift off the pipework and eyeball the beans.

If you have any more questions just ask.


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## wan (Oct 19, 2016)

Thank you @CJV8 for this idea.

here is my DIY;

I'm using a can (recycle)cutting the middle and order flexible aluminium pipe 70mm and finish with courier box(temporary for collecting chaff).

Thermometer next step.


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## Nerdlinger (Jan 10, 2020)

I increased weight to 130g and got a darkish roast on the second batch, when the popper was still warm. This batch was very good but most of the other batches were disappointing to varying degrees. I think it is just that I need a darker roast and while I have managed this with the air popper it has proven difficult and it's noisy. I got that Bocaboca...


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