you can also try to enlarge the internal vent holes in the metal wall.
Started experimenting with modifications to the quick popper to try and push out my roasting times, results not too bad, I drilled a heap of holes around the base hoping that by allowig more air to be able to be sucked in, the temps would drop or ramp more slowly, seems to be somewhat on the right track, more holes will be made soon and results reported.
Managed to get to 4 minutes for first crack, but seemed to start with the smoke fairly shortly after that and pulled it between 4:30 and 5:00. (Perhaps Im freaking out a bit). This was with holding the fan above the top to blow heaps of fresh air down into the "chamber".
My biggest concern I have is that the beans if pulled later seem to come out looking very oily, not nessesarily too dark, but not a nice matt sheen on the outside of the beans. If I pull earlier I get beans lighter perhaps a tad grassy/lemony.
I did three roasts of the Brazillian Pulped from the greenbay last night, and got a light, med and dark roast, with the light being not too bad looking outside oil wise (none), but the medium with a little bit and the dark somewhat oily looking. Put each in separate brand new ziplock bags (not ziplocked) and put into a shared one way valved bag, for degassing.
Tried an examplar bean with each of them with a crunch test - they all had different flavour profiles, I suspect 10% light, 85% medium, 5% dark would make a nice combo based on the tastes. The little one (20 months old) was assisting with the roast, managed to yoink one off the cooling try and gobbled it up, when asked what she thought, "mmmmmm" was the response, I suspect I may have a future CS on my hands. *::) May she learn more than me, and keep me supplied with decent coffee as I get older. (And may she not do it again - the Mrs is convinced that was the reason she took forever to get to sleep last night * :D )
you can also try to enlarge the internal vent holes in the metal wall.
As well as getting more cool air in you need to get trapped hot air out.
Hot air can be trapped in the upper body of the popper (surrounding the roasting chamber).
I recommend more holes to get this trapped heated air out.
As mentioned yesterday in another thread, tilting the Popper forward also helps a lot by allowing for a less resistant path for the hot air to circulate and exhaust. This also improves bean agitation too, by quite a lot actually and helps with the creation of very evenly roasted batches. In my case and with a Glass Chimney fitted (ex Hurricane Lamp), I used a small piece of 25mm thick pine placed under the back of the Popper. Worked really well at this angle...Originally Posted by 18372C3B2E31293B2C5E0 link=1293068907/1#1 date=1293072872
Pretty sure all of the gems for Popper Roasting are contained within a single thread under Roasters and well worth the read if you can find the time.... ;)
If you are using a chimney would drilling some holes in the chimney be an easy experiment?
My thoughts were that this would let the heat dissipate more and reduce the build up of heat in the popper and the beans.
I have been finding 20 seconds after the start of second crack produces a roast I quite like.
I have been getting times in the order of 8 minutes with my machine.
It is worth having a timer this stops you losing your nerve and stopping early.
Easy to test... Drill a few in the upper section of the chimney and see what happens. Tin cans are easy enough to get hold of if doesnt work out as expected... ;)Originally Posted by 2C2726172629213A26480 link=1293068907/4#4 date=1293102178
Youve got to be careful using timers with a Popper or any other form of roasting that is significantly affected by changing ambient temperatures. Better to think of stop-watches et al as just part of the overall toolkit and not something to use as an empirical measure. Using all the senses with an occasional glance at a Timer/Stop-Watch is the way to go I think..... 8-)Originally Posted by 2C2726172629213A26480 link=1293068907/4#4 date=1293102178
Youd be surprised just how hard getting hold of cans are in this household, there is a request for all to be kept for my "experiments", and thus far managed to get one that did not make it out to the kerb. I will definitely play about with some chimney holes too. The best bit about the chimney is the reduction in product loss.
My biggest issue is getting rid of heat. Im pretty sure based on the darkness of the roast and the oilyness (and weight loss of ~21%) that Im pulling them late (unless there is a phase between first crack and second crack during roasting where this is supposed to burn off?) With the break next week, I might look at some ambient air induction fan -> funnel -> pipe dumped into the roasting chamber and see what happens. Ive also got some more holes to drill. Just thought Id keep posting results and grabbing feedback as this is so new, I could be doing something so wrong bean roasting wise and am just missing that "ah-ha" moment.
There is also a plan for a roasting cooler to be constructed perhaps getting the bean cooler more efficiently will let me push the roast just that little bit and be able to stop it 100% when I stop it. :-/
If I compare colour with say the same green bean with the roasted version from Andy I can usually get the same colour, although my roast went by in 3-4 minutes and my beans are much more oily. Taste wise well I can pick up everything Andys get, but mine are definitely not as smooth and clean on the palate, the saving grace is with milk the Mrs cant pick it and its still more enjoyable than coffee I get from a shop, so Im wasting money with the experiments. It just takes a while for them to be completed, and am starting to go through a lot of green beans ::). The youtube clips for people roasting seem to have them come out with black pills of oil covered ("I dont think it should look like thats"-me). I think the popper is not quite tweaked to get enough control. I may get there, I may yet give up and go behmor or baby+gasmate (especially when some popper mods like dimmer switches start getting 1/3rd the way to one of these) - but it would be nice to be able to push out a consistent roast summer (and winter) out of the popper in the interim.
After starting my roasting experience a few months ago in Qlds warm weather, I too found that 4-6mins was about all I could stretch a roast out till 2nd crack. Even with a fan flat out 200mm away it would never go over 7mins in the early morning cold of 18deg. My solution was to cut a hole in the front and rear of the plastic cover 10cm by 7cm by using a scoring tool. By using that rather than cutting through all sides the bottom score is not right through on the front and on the side of the curved back so it works like a flap that can be closed to finish the roast if more heat is required. By varying the fan speed and distance away I can now get 110g roast 1st crack 8min and extend 2nd as far as you like (have taken to 19mins just to see) by fan speed and distance. Im sure this will also help the popper last longer as it is receiving cool air on the outside of the chamber. I also leave the fan pointed at the popper after roast while cooling beans and it is cool to touch in less than 5mins. That said I better get off to the P.O box and see if my Behmor has arrived from Andy. :) [smiley=thumbsup.gif]
The flavour profile youre picking up, compared to Andys roasted in a commercial drum roaster, is quite typical for a Fluid Bed Roaster; like a Popper. You do tend to end up with brighter results in the cup but this can be mitigated to some extent if you keep beavering away with mods to your unit, to slow it down some.Originally Posted by 5E525F5F5A565E5054330 link=1293068907/6#6 date=1293135673
Personally, I think youre going about the process in exactly the right way. Ultimately, which roaster you decide upon should probably be dictated by your coffee consumption compared to how often you want to roast. Larger batch capacities will certainly allow you to reduce the frequency of roasting down to once per week or thereabouts. With judicious, targeted mods on the Popper, it is possible to roast batches from 150g-200g at a time but definitely not more than this as it just becomes too much mucking around to manage.
Probably, the singular most annoying aspect with Popper Roasting, is that the blower fans are made of brittle plastic these days and eventually (after umpteen heating-cooling cycles) they do disintegrate or chew up the fan hub. Older Poppers seem to be more immune from this annoyance.
So, if batch sizes of this weight will meet your needs then maybe a Popper is worth additional mods and sticking with for some time to come. If larger batches are foreseen in the near future, then maybe just leave the Popper as is (for small blend components for example) and look to building a Corretto, buying a Behmor as you mentioned or construct a KKTO... Lots of options if bigger batches are going to be the norm...
Anyway mate, keep at it. All the knowledge being gained is gold, no matter which roasting method you eventually decide to go with.... ;) 8-)
All the best,
I must admit I look at the popper as a learning tool and if it dies I will probably get something more robust and with greater capacity.
The popper does have the advantage that it is easy to see what is happening.
At best they are a workable compromise at worst they really are not designed for the job and so are putting yourself at a disadvantage before you start.
But as long as you are having fun the rest is really just details.
After all you donít need the best equipment on the planet to make a lot better coffee than most people drink.
Well I have tried some more of my roasts and even had feedback from others.
(Drilled popper - roasted on Monday) Did a three way Brazil Natural Pulped - pulled when just after first crack about 3:30. A fairly light roast. Pulled one at 3:45-3:50 a medium/dark roast with just a hint of oil on the beans and pulled one at 4:10-4:15 just as the first whisps of smoke started to come off. Took this one into the guy at work who has a drip thing he sticks over his mug. Trying to edu-ma-kate him that even my home roasts freshly ground (Zass hand jobbie) will taste better than the pre-ground stuff hes grabbing from the supermarket. Feedback was that he liked the light one one of the best hed had bar some blue mountain he grabbed from Jamaica when he was over there 7 years back.
Now I dont think that its even close to the JBM (something now on my must try list) but he seems to be amenable to education, hopefully this will lead to some form of better equipment at work ;).
Mysore - roasted 20/12 - fairly dark, very oily. Pulled at 3:00-3:30 (pre-drilling).
The oiliness freaked me out, still does, however in the cup, I enjoyed this one, although was a tad "smoked" in character, to be expected I suppose. The wife said, she enjoyed it, but would prefer it without the smokiness, but perhaps most encouragingly she said that I better get more beans and keep practising. Shes been most supportive and has loved the coffees produced from the popper. (To be honest so I have too!). Got some of the best grind/tamp consistency yet with near perfect 50-60mL in 25-30 seconds with that beautiful dark flow @ a honey off a spoon rate.
I am currently treating the popper as an experiment if it works will head on to some kind of upgraded equipment. Have been pricing up parts for a Coretto or a KKTM and comparing it to things like the baby roaster (copper spinny thing over gas) and a behmor. From what my research is indicating either of the latter two would be suitable. Im hesitant to go Coretto or KKTM because of some space constraints at the moment, little ones getting into things and the very strong likelihood of getting very carried away.
Im using a couple of different poppers and find that drilling holes in the base definately slows things down.
I also tilt and jiggle the popper for the first 3-4 minutes of the roast, then sit it on an angle of about 30 degrees, steadily bringing it more upright as the roast progresses. This slows it all down further and allows more (120g) beans per batch.
Doing these things, Ive stretched time to first crack from about 3-4 min. to 6-7 min. on average. 2nd crack at around 11-14 min.
On cooler Melbourne days, I sometimes need to partially cover the chimney to reach 2nd crack.
Also, a bean cooler, if you dont alreay have one, is very handy thing. It saves time and makes roasting that 2nd batch much less of a chore, especially if you can use it to cool the popper after the beans are cooled.