Advice Please: Coffee-Tech Ghibli RoR

[roblawes]

Hey guys, just wondering if anyone has advice on the airflow control with the coffee-tech ghibli 15kg? Recently started using cropster and Im trying to decrease the RoR throughout the roast, but struggling with this. At best I get flatlined RoR.
Seems that with the ghibli when you boost the airflow it actually boosts the RoR, which seems backwards to me?

 

[Musicphan]

I'm not familiar with that roaster but you can increase airflow too much which will boost RoR.. in fact you have to be aware of this going into FC. Does your roaster have variable airflow?

 

[MillCityRoasters]

Hey guys, just wondering if anyone has advice on the airflow control with the coffee-tech ghibli 15kg? Recently started using cropster and Im trying to decrease the RoR throughout the roast, but struggling with this. At best I get flatlined RoR.
Seems that with the ghibli when you boost the airflow it actually boosts the RoR, which seems backwards to me?

The Ghibli has a pre-mix power burner. That means it has a fan on the burner that injects air and gas in different proportions relative to the desired heat level. This means your roaster exhaust and burner are sometimes interacting with each other in highly unexpected ways.

Many roaster manufacturers use this system (usually from Weishaupt or Honeywell) as a it's a pre-packaged, off the shelf, drop in UL/CSA internationally certified solution. Sadly, it kind of s-cks when you are trying to precisely control the application of heat when roasting speciality coffee.

Eventually, you'll get enough experience on the roaster to figure out optimal settings (batch size, preheat temp, airflow, drum speed, and heat level) that minimize the need for changes in those setting throughout the roast. It's helpful sometimes to simply turn the burner off and on during the roast. Perhaps preheating higher and "coasting" through the first minute or turning off the burner coming into first crack and "coasting" through a period of development time.

The Ghibli is a well designed and well constructed roaster. You can absolutely coax good coffee out of it. It just requires that you be a little more creative to manipulate your roast profile. Or shift your graph up and to the right into the darker roast territory it's more specifically designed for.

 

[roblawes]

The Ghibli has a pre-mix power burner. That means it has a fan on the burner that injects air and gas in different proportions relative to the desired heat level. This means your roaster exhaust and burner are sometimes interacting with each other in highly unexpected ways.

Many roaster manufacturers use this system (usually from Weishaupt or Honeywell) as a it's a pre-packaged, off the shelf, drop in UL/CSA internationally certified solution. Sadly, it kind of s-cks when you are trying to precisely control the application of heat when roasting speciality coffee.

Eventually, you'll get enough experience on the roaster to figure out optimal settings (batch size, preheat temp, airflow, drum speed, and heat level) that minimize the need for changes in those setting throughout the roast. It's helpful sometimes to simply turn the burner off and on during the roast. Perhaps preheating higher and "coasting" through the first minute or turning off the burner coming into first crack and "coasting" through a period of development time.

The Ghibli is a well designed and well constructed roaster. You can absolutely coax good coffee out of it. It just requires that you be a little more creative to manipulate your roast profile. Or shift your graph up and to the right into the darker roast territory it's more specifically designed for.

Nice one Steve! Thanks,

Do you know about the 'F' settings on the airflow control? Am I right in guessing that 'F70' is the max airflow & the lower the number, the lower the airflow?
Is there any way of getting the burner to kick in as soon as you hit the 'burner on' button? Ours kicks in about 10-20 seconds after youv'e turned it on. I have had a go at switching it off during the roast but just caused the RoR to plummet, so I guess I will have to try flicking it off/on quickly.

Thanks again for the help, really good to speak to someone clued up on the equipment!

 

[MillCityRoasters]

Nice one Steve! Thanks,

Do you know about the 'F' settings on the airflow control? Am I right in guessing that 'F70' is the max airflow & the lower the number, the lower the airflow?
Is there any way of getting the burner to kick in as soon as you hit the 'burner on' button? Ours kicks in about 10-20 seconds after youv'e turned it on. I have had a go at switching it off during the roast but just caused the RoR to plummet, so I guess I will have to try flicking it off/on quickly.

Thanks again for the help, really good to speak to someone clued up on the equipment!

Your burner is programmed with a purge cycle that won't allow instant ignition. You'll have to really game the timing of cycling the burner at times that won't affect the roast too badly.

 

[sae]

Your burner is programmed with a purge cycle that won't allow instant ignition. You'll have to really game the timing of cycling the burner at times that won't affect the roast too badly.

Do you think you could just cut the gas but keep the fan going? I don't think this would initiate the purge cycle then.