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Thread: Observations on fixed output vs adjustable heat gun in a Corretto setup…

  1. #1
    Life-long Learner DesigningByCoffee's Avatar
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    Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi folks
    Well. you know how it is. Bit of tinkering in the shed, a trip or two to Bunnings, one thing leads to another… :-)

    So I thought Id post about the reasons why Ive gone from a fixed output Ryobi 2000w gun to a Bosch PHG 630 adjustable heat gun, and the differences if any, it made.

    So, my basic Corretto setup is a Breville BBM100 with splitter modified & fire blanket insulated pan, triple insulated lid (2 layers of hardiplank over aluminium shield) and DMM. I have up till now been using a fixed temp Ryobi gun on an adjustable lighting tripod, with various extensions & chimneys to allow me to get the gun high enough for a pretty effective setup, allowing 13min to first crack, 6min to second crack repeatably.


    The disadvantages of this setup were:
    • the tripod takes up most of the bench!
    • Adjustment was a two handed, fiddly affair
    • I couldnt, no matter how high the gun was, get a slow start to the roast - straight to 20deg/min once initial warming kicked in.
    • the ramp from first crack to second crack was always accelerating at the end, unless adjusting height every minute or so.
    • The higher the gun, the less the airflow in the pan

    The advantages of the new setup as seen so far include:
    • much smaller footprint, and all the bits are contained
    • one finger adjustment of heat, in small increments
    • consistent airflow throughout the roast.
    • everything is much lower & generally easier to get to.

    Interesting points about the new gun:
    • much quieter
    • very well made - easy adjustments - very precise (one finger push in 10deg increments)
    • generally less airflow, even at speed 3, than the ryobi - but not sure what impact this will have.

    While Im still getting a handle on the various setting & changes in input required to get to my profiles, my initial reflections on the first few roasts:
    • Slower airflow seems to give a much gentler heat, as does the adjustably of the gun.
    • For some reason, there was much less chaff left in the pan/on the beans? Maybe rather than throwing it off in sheets with the higher airflow it roasts it quite fine & brittle then it just gets ground up then ejected or sucked through the cooler?
    • The ramp between first crack & second crack was amazingly controlled - almost no accelerating at all.
    • Had a much more pronounced rice bubble second crack - with the ryobi Id get a tiny bit of this then serious first crack like cracks.
    • Overall much easier to handle.

    In the cup?
    So far so good! Im only two roasts down so far (the first was too long at 25 mins, the second a bit short as I got the settings on the gun into the zone) but even then both roasts seem pretty good.

    So overall, really happy with the move, and looking forward to polishing the results. Only downside is I will now need to strip all the construction adhesive of our old brick wall with the Ryobi!

    Shouldve thought of that

    Will keep you all informed!

    Matt







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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Hi Matt,

    Im using the same gun in an uncovered corretto and I find it really good to control the ramp. I usually start it off at about 300C on full fan and gradually increase it to around 500C to achieve first crack at about the 13 min mark and second crack around 6 mins later.

    I dont know about getting a slow start as it always goes to about 21-22 deg/min and I havent tried to change this. However, the ramp to first crack is a straight line @ 12 deg/min with the control you get from this gun.

    I would be interested to know what the difference is with maybe a constant ramp from load to first crack. I would imagine you would have to start and maintain about 15 deg/min to achieve this.

    I am more than happy with the results in the cup but we are always open to tweaking our methods. Hope to hear more of your exploits and welcome to the Bosch club.

    G.

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    Life-long Learner DesigningByCoffee's Avatar
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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Quote Originally Posted by 5A4A5C444B484E290 link=1336013860/1#1 date=1336016095
    Im using the same gun in an uncovered corretto and I find it really good to control the ramp.* I usually start it off at about 300C on full fan and gradually increase it to around 500C to achieve first crack at about the 13 min mark and second crack around 6 mins later.

    Hi Greybeard
    I agree. Ive found that both with the new gun and the old a constant temp input to first crack always gave a reducing curve profile - therefore my technique has been to start gently (around 380 on this gun) then increase by amounts at 125/150/175 degrees, giving a pretty flat climb to first crack, dropping again at 195 degrees to the input I started with, then dropping it again at 210 when rolling first crack is finished to 350 - this then gives a really even climb to the drop zone at 223-24 ish.

    Im amazed how controllable it all is!
    Matt

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    Senior Member Beanz.'s Avatar
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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Good to see some discussion on variable temp control as it allows so much more experimentation. I use an old theatre lighting dimmer to vary the output on my heat gun which gives excellent temperature control. Effectively the same process. One notable point is that I never need to run the gun at 100% output whereas with no control the gun is running flat out. I typicallly run 320g roasts in the corretto so I guess if I ran large Qty then I may require higher output. The best feature is the ability to vary the deg/min at various points in the roast. Following Joseph Riveras lecture at the first Beanology I always slow the rate of climb between 150 and 180 Deg to try and get the best out of the beans. Joseph talked about the Maillard Reaction at 154 to 160 Deg and Caramlization at 110 - 180, by slowing the Deg/Min you get to play with these parts of the roast. Hope my memory is correct on these specific temps! With temp control you can pull back the heat input once first crack is underway, you can also push it harder if things seem to be stalling. I also have a lid on the breadmaker which I remove at R1C this allows me to check bean colour better and also flattens out the temperature rise so things do not run away at the end of the roast. I consider the ability to control temperature the most important aspect of my corretto roasting. I get frustrated using another roaster when I cannot control the heat input during the cycle.

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    Life-long Learner DesigningByCoffee's Avatar
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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Quote Originally Posted by 536C757C6A464B190 link=1336013860/3#3 date=1336032755
    Following Joseph Riveras lecture at the first Beanology I always slow the rate of climb between 150 and 180 Deg to try and get the best out of the beans.
    Hi Beanz
    Interesting. Do you therefore hit it hard at the beginning and then back off in this range? I always found a hard start led to divots…
    Also, do you actually reduce the temp in this range, or just not increase it further? There is always a natural decrease in the climb in this range anyway, even under constant input - so wondering if you cut right back and coast more…

    Matt

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    Senior Member Yelta's Avatar
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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Ive been using a Bosch 630 with a single loaf Breville BM for about three years, I monitor temp with a DMM and stainless probe inserted in the bean mass just above the paddle.
    I roast 725 grams of green beans once a week.
    I start everything from cold, heat gun set at about 600c and reach first crack at almost spot on 200c @ about 13 mins every time, I then drop the temp to about 550c and let it run to between 225 and 230c, judgement is needed here, some beans roast and look fine @ 225 while others are a little light and need that extra few degrees to finish them off. :)

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    Senior Member Beanz.'s Avatar
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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Quote Originally Posted by 1736203A343D3A3D34112A103C35353636530 link=1336013860/4#4 date=1336093905
    do you actually reduce the temp in this range, or just not increase it further?
    Approaching the 150 Degrees I typically aim to slow the climb to 12 deg/min rise but sometimes it might be more aggressive ie 15. Between 150 and 180 I still increase the temperature but aim for 10 and no more than 12 degrees / minute After 180 I then increase the rate a few degrees and at first crack back off the heat to slow the rate as much as possible but without running into a negative temp ramp.
    I would love some feedback from more experienced roasters as this has been established by my own roasting experiments.
    I find the Yemen beans the hardest to roast as they can go from perfect to overdone very quickly so the final few minutes are quite critical.
    You might like to read another thread where KJM had some good feedback on changing the profiles and the result in the cup, Mal also listed a reference http://coffeesnobs.com.au/YaBB.pl?num=1307254012/8#8

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    Life-long Learner DesigningByCoffee's Avatar
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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Quote Originally Posted by 407F666F7955580A0 link=1336013860/6#6 date=1336111564
    You might like to read another thread where KJM had some good feedback on changing the profiles and the result in the cup, Mal also listed a reference http://coffeesnobs.com.au/YaBB.pl?num=1307254012/8#8
    Mmmmmm… Interesting! Certainly there is plenty of scope for experimenting when you can actually achieve a consistent, repeatable result.
    It seems that maybe starting slow, ramping up 150 then slowing to 160, then ramping again might have some impact? Ill need to have a play!

    Also, after 2 roast over the weekend, Im truly amazed how controllable this new setup is compared to the fixed temp HG. Once I got the input temps into the zone, the profile is soooo smooth (13mins to first crack, then 6mins to second crack - see my old fashioned, hand recorded profile!)

    To add adjustments for ambient, different beans etc is probably only 10 deg away on the settings… sweet :)

    Ill let you know how it cups…

    Matt


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    Re: Observations on fixed output vs adjustable heat gun in a Corretto setup…

    Well folks
    Just an update, Im getting consistently better roasts with this new setup. Much more controllable between first crack & second crack, and infinitely adjustable everywhere else. The old setup allowed for a solid, repeatable profile but really only seemed to want one sort of curve! You could just shorten or lengthen it - not really change/ramp it too much. This setup will allow for much more experimentation.

    Couple of interesting observations:

    • While first crack is bang on what I have been achieving for the last 6 months (@ 199deg) second crack seems to come on 2-3 degrees earlier in this setup. Im now pulling roasts at 220-221, where 223-224 was much more the ticket before. This might have to do with more heat/less airflow - but is giving a roast that is lighter in colour but still fuller & richer in flavour - a 221 drop would have been quite sour previously.

    • second crack is much more consistent with what Ive read from others experiences - a genuine rolling rice bubble rustle (if ive left it that long - which Im trying not to do now!) rather than a hint of this then substantial cracks. All smoke & mirrors maybe, but interesting to see!

    Anyhow, happy roasting all - and I thoroughly recommend the Bosch if youre in the market for a new HG!
    Matt


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    Life-long Learner DesigningByCoffee's Avatar
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    Hi folks
    Just an update - after a bit of T&E this latest setup is finally giving me the best results I've ever had home roasting. So easy to control & repeat!
    If anyone is interested, I've just gone live with my first feature film, justing showing the setup & basic roast process/profile :-)

    Coretto Roast - YouTube

    Happy roasting!
    Matt
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    Mal Dimal's Avatar
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    I'm with you Matt...

    I'd never go back to a Fixed Output HG Corretto setup. The quality of the roast batches since making the move have just been much more consistent and it is much easier to tailor a batch profile when aiming for specific outcomes - The name of the game I believe....

    Mal.

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    Life-long Learner DesigningByCoffee's Avatar
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    Thanks Mal
    I agree - I can almost set my watch by my roasts now! I can also see how you could easily adjust a profile to suit different SO beans - the results are just that consistent & repeatable, and fine tuning so precise.
    I just need to get enough customers so I can try post blend roasting! :-)

    Matt

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    Senior Member Beanz.'s Avatar
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    Quote Originally Posted by DesigningByCoffee View Post
    Hi folks
    I've just gone live with my first feature film, justing showing the setup & basic roast process/profile :-)

    Coretto Roast - YouTube

    Happy roasting!
    Matt
    I was sure I could smell the beans roasting while I watched the video ! Looks good.

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    Life-long Learner DesigningByCoffee's Avatar
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    You certainly get some great toasty roasting smells early on - but the end-of-roast smoke aroma less so! And I should know - my work office is in the back of that shed - the smell can last for days! :-)

    Matt

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    My cheapo HG died yesterday just prior to first crack. Very sad for the 500g of beans, I did try to resurrect them this afternoon but I don't think they will be very nice...

    I bought the PHG 630 and just ordered multimeter ect from Bean Bay, apparently already posted, which means going by ST recent efforts with beans it could be here tomorrow sometime! Gotta say the service from BeanBay is very awesome.
    Anyway this is scary, its like starting all over again, this thread is very helpful though.

    Another step towards better and more consistent coffee.

    Thanks

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by Steve82 View Post
    I bought the PHG 630 and just ordered multimeter ect from Bean Bay, apparently already posted, which means going by ST recent efforts with beans it could be here tomorrow sometime! Gotta say the service from BeanBay is very awesome.
    Anyway this is scary, its like starting all over again, this thread is very helpful though.
    Thanks
    Excellent choice of heat gun Steve, I've had a Bosch 630 for over 20 years, it's still going strong, looks like the've come down in price as well, around the $100 now.

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    Quote Originally Posted by Yelta View Post
    Excellent choice of heat gun Steve, I've had a Bosch 630 for over 20 years, it's still going strong, looks like the've come down in price as well, around the $100 now.
    Yeah there was no other choice in my mind, $99 from the big green shed, digital push button temp control, right up my alley! haha

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    I've been using an ozito adjustable HG from Bunnings in a coretto for at least 3 years now, still going strong. Happy with it particularly given the price.
    Adjustable is a good thing. Its also removed a pile of glue stripping a lino floor, and other paint in that time successfully.

    Word of warning for HG - do *not* leave lying around on a bench where a cat can find it and pee on it. An older HG suffered that fate.

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    Senior Member ozscott's Avatar
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    Anyone else having problems with this gun overheating and dropping it's temp down automatically to protect itself?

    Cheers

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by ozscott View Post
    Anyone else having problems with this gun overheating and dropping it's temp down automatically to protect itself?

    Cheers
    Do you mean an Ozito HG? I've been using a Bosch for 10 + years, never a problem.

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    Senior Member ozscott's Avatar
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    Hi Yelta. Yes the Bosch mate. I have cleaned it out gently with compressed air (I have probably had it for 6 years or so) but still problematic. It may need better cooling airflow over it from a fan closer by. Cheers

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by ozscott View Post
    Hi Yelta. Yes the Bosch mate. I have cleaned it out gently with compressed air (I have probably had it for 6 years or so) but still problematic. It may need better cooling airflow over it from a fan closer by. Cheers
    From memory, I think mine is the 630 model.

    The intake mesh will clog with chaff and need regular cleaning, have never had the gun shut off, I use a stiff brush regularly, also have a pedestal fan set up to blow chaff away from the setup.

    I run the gun on medium fan, maximum temp I use is 550°C, usually closer to 500°.
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    Senior Member ozscott's Avatar
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    I will try medium fan. I normally roast 1kg and it often reduces it's heat output to avoid overheat...plays havoc with the roast when that happens.

    Cheers

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by ozscott View Post
    plays havoc with the roast when that happens.Cheers
    I can imagine, my maximum is 750 grams of green in a converted single loaf Breville.

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    Quote Originally Posted by ozscott View Post
    Hi Yelta. Yes the Bosch mate. I have cleaned it out gently with compressed air (I have probably had it for 6 years or so) but still problematic. It may need better cooling airflow over it from a fan closer by. Cheers
    I've had it happen a few times. I have a fan pointed at it which also goes over the top of the roaster to blow the chaff away from my keyboard as it exits my chute, but it still happened with a low flow so I had to up it to a medium speed. it's not a gentle breeze but still not tornado strength either.
    My Ryobi has roasted about 100KG of coffee over a six year period so I had looked at buying another one, but the problem hasn't occurred since I put a bit more air over the gun.

    I roast with high fan and 550g charge weight. I found that I could use lower heat temps pushing more air with the gun. Max is usually 420 - 440. I'd like to use both speeds during different parts of the roast but can't see how to bridge the different temperature requirements between the two speeds and keep a decent profile.

    I'm in Qld and have pretty much roasted outside every week for the past six years, and during the hot days this summer it still didn't drop off so I'm guessing the fan works. Who knows though, it's electronic componentry ,it does some weird stuff at times when it gets older and stressed.

    I reckon some cooling air could help you out.
    Last edited by doobs; 3rd March 2019 at 06:27 PM. Reason: additional info
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    Senior Member Stan's Avatar
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    I have always had a fan blowing over the heat gun and blowing the chaf away. I use a Bosch 630? This the 4th gun I have had in 11 years and has by far lasted the longest. I use a similar highest temp of 560 but normally lower at about 530 but I vary the temp to the conditions on the day. I roast 600g normally but have gone up to 700 with a breville single loaf machine. I also vary the temp depending on the bean. I usually try for 14 minute roasts and I allow the temp drop a few degrees after 1st crack and finish at the start of second crack. I like a darker roast

  27. #27
    Senior Member ozscott's Avatar
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    Behmor Coffee Roaster
    Yep I use a fan but had backed it off. Further away. Will bring it back closer. Cheers



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