Between-roast routine on gas roaster

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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#1: Post by beanman »

I tried searching, and couldn't find anything here specific to between roast routine.

I have about 25 roasts on my BC-2, and need to start doing back to back roasts to not waste the warmup/cooldown time on one roast.
What things do I need to do between the roasts?
I'm sure "it depends" is a good answer, but your advice will give a starting point to try, then modify to suit my needs.
One thing I read on the 'net was be consistent on the drop door open time (controls air/heat loss repetition)
What ET for my second charge? For one roast, I heat to 450F, turn gas to .6 kpa,and charge at 400F.
I've been dropping at 410F BT, and ET is just below 400F.
Since the second roast will most likely have a hotter/heat-soaked roaster, should I charge at a slightly lower temp?
Am I still looking for the same TP on the next roast? Current roasts are 190F TP.

I'll most likely do a decaf on the second roast (yea, I know, decaf - but I try to control my caffeine intake . . .), and I know decafs generally roast quicker, so that will be a learning curve also.

Thanks in advance for the info.

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#2: Post by mkane »

Yesterday we did nine roasts in succession.

First roast was charged @ 350°

Last roast @ 310°

TP was almost the same each roast.

Were not shooting for repeatability. The BC-1 retains lot's of heat. I could probably do a 100g roast as the 10th and never light the burner,

We preheat the machine 15 minutes or until it's case it hot to the touch.

In between we idle @ .5 kPa


#3: Post by aabud »

What I do...not to be necessarily equated by what should be done... :-)

I'm BC-2 also, so will speak in those terms.

I charge at BT 160C degrees. Pre-roast, I like to be around above 200C on both BT and ET, and set the gas to my post soak Kpa, which is 3.5, then turn off the gas with the ROAST button, and let the temp fall down to 160, at which point I charge. I soak for 90 seconds, then hit the ROAST button which fires up the burner at the preset of 3.5kpa. I like to see BT and ET within 10 degrees C of each other at charge (so BT at 160, ET at 160-170), and use more or less air as I'm falling down from 200C to even things out if BT and ET are too far apart. Not sure how important the BT ET spread is, but noticed them being closer at charge on some of my better roasts, so have been paying attention to that lately. As I've posted in other threads, I've had good luck with a pretty low airflow (4 pascals), which on my damper dial is somewhere between 2 and 3, with the fan control at 100%.

Post roast, I turn the gas to between .5 and 1 Kpa or so, and let it run while I tend to the roast that finished. When I'm ready to roast the next batch, BT/ET will have risen north of 200C, so same drill as above. If I see it go above 230C between batches I'll drop the gas to just keep it above 200C.

For the first roast of the day, I set gas to 2 or 3KPA for a few minutes to get the temp up, then run at 1KPA or so for 15 minutes to keep the temp up above 200C. Again, I don't let it go higher than 230C or so, without dropping the gas to keep it 200-230C.

Hope that helps.

beanman (original poster)
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#4: Post by beanman (original poster) »

Thanks everyone.
Looks like I need to find the gas that helps me get to and stabilize at my 400F charge temp. I can hold 400F while I save the previous Artisan file, etc, then turn gas down and let the roaster cool down to maybe 390F for the next charge.
It boils down to create a plan, take notes, analyze, and tweak.


#5: Post by hellojava »

Scott Raos book describes a between batch protocol that I use on my gas cormorant.

I let the roaster heat up 40 F above my charge temperature for about 15 minutes before starting my first roast.

I cut the gas after I drop my previous roast, and I allow the machine to drop 40 degrees F below the charge temperature for my next batch. This allows my roaster to build momentum and run the next batch as if it was running its first batch.

For example: if my charge temperature is 380F, I will heat the machine at 420F for 15 minutes, slowly bring it down to 380F in 5 minutes, cut the gas, at 340F I will turn the gas on, and at 380F I'll charge my beans.

Once the roast finishes, I'll cut the gas and let the temperature fall to 340F. I'll turn on the gas, load my next charge, and charge at 380F.

The key here is that I am consistent about starting my roaster at 340F for every roast and charging my beans at 380F.

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#6: Post by CarefreeBuzzBuzz »

Artisan Quick Start Guide

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#7: Post by Brewzologist »

+1 On Scott Rao's CRBP book info on warmup and between batch protocols.

+1 on using the PID control in Artisan if your roaster has one. I created my initial warmup and between batch protocol's from Rao's recommendations and push a button to start them in Artisan. This has increased my consistency and it frees you up for other tasks too.

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beanman (original poster)
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#8: Post by beanman (original poster) »

OK, more great info.
Just ordered Scott Rao's CRBP from Sweet Maria's. Been wanting it anyway, so good reason to pull the trigger. But why did a $45 book become a $95 order? :o Always a few more things we can add to an order, right?
The consistent ramp up or down to charge temp sounds very logical. Since my first roast is preheat to 450F, then reduce gas to .6 kpa and ramp down to 400F for charge, I'll try up increasing to maybe 420F, then .6 kpa to ramp down to 400F.

And I'm amazed how much Artisan can do. Won't use it for BBP right away, but I need to continue tweaking Alarms to help me be a better roaster.

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#9: Post by mkane »

A thousand roasts in you won't need alarms

beanman (original poster)
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#10: Post by beanman (original poster) »

A few days ago I did my first back to back roast.
I had my daughter taking notes so I could focus on the roaster.
I need to get better at saving the Artisan profile and getting it ready for the next roast!
And I need to remember to close the charge door -- I wondered why the air flow wasn't normal . . .
But I got some info on gas settings for letting the roaster cool down a bit, then back on to resemble my initial preheat.
It will take a few roasts, but I'll figure it out.
I gave both roasts to my sister, so I can try it again soon.