11 replies to this topic

[FodfoodsafetyKate]

Hi all, bit of a new one for me. I am working with a coffee roaster and I am trying to find a way of validating that their roaster is achieving what the digital dial says (thats the one roaster). On the other one (an older model) only has a dial to select the desired temperature. Does anyone know of any ideal ways of validating these machines? Thanks 

[SUSHIL]

You can Contact the Company doing Callibration work of Digital and Analog Dials Thermometers.
Also you can keep one Callibrated Dial or Thermometer to periodically verify your Roaster Dials.

Edited by SUSHIL, 29 June 2021 - 11:17 AM.

[Scampi]

Spouse is employed in same category, when you said old roaster, i'm betting you mean in the 50 year old range! 

 

You may just want to use a calibrated infra red thermometer to measure the surface temp of the kettle 

 

As the roasters use a source of combustion, you'll likely find quite a bit of variability (depending on fuel source) 

 

Assuming the dial and the infra red and both calibrated properly, you should be able to be +/-  5F

[Charles.C]

Hi all, bit of a new one for me. I am working with a coffee roaster and I am trying to find a way of validating that their roaster is achieving what the digital dial says (thats the one roaster). On the other one (an older model) only has a dial to select the desired temperature. Does anyone know of any ideal ways of validating these machines? Thanks 

 

There are presumably some similarities to validating  "ovens" as used for cooking (described in the Literature). so that, as per Scampi, you need to determine the uniformity involved.

 

What is the approx. expected temperature range involved ? (I don't drink coffee, roasted or otherwise )

 

How much accuracy do you seek with regard to the actual vs indicated settings ? (TCs often get very dodgy >100degC and <0 degC, I anticipate IRs have similar limitations) (the usual problem is that the temp. curve is non-linear).

[Ted S]

Good morning. There are "data loggers" that are used for this exact type of application. Many data loggers are designed to be food safe and can be added directly into the cooking vessel (ie. coffee roaster, etc...) along with the food item that is being cooked, roasted, etc.... I have used data loggers in the past to validate a steam jacketed kettle cooking operation where the data logger that I used looked like a very large stainless steel "pill". We would add the data logger directly into the batch of sauce that we were cooking (200*F) and the data logger would then take temperature measurements (at a frequency that you can program) while it is in the product being cooked. Once the cooking process is over, the data logger gets recovered and the data is then downloaded to a software package. The data logger opens up and attaches to a computer via mini USB port. The one that I have used most recent costed ~ $500 US. Price will be dependent on accuracy required and the type of application that you need. If you search the Internet for Data Loggers, you will see many choices available. Hope this helps. 

[Charles.C]

Good morning. There are "data loggers" that are used for this exact type of application. Many data loggers are designed to be food safe and can be added directly into the cooking vessel (ie. coffee roaster, etc...) along with the food item that is being cooked, roasted, etc.... I have used data loggers in the past to validate a steam jacketed kettle cooking operation where the data logger that I used looked like a very large stainless steel "pill". We would add the data logger directly into the batch of sauce that we were cooking (200*F) and the data logger would then take temperature measurements (at a frequency that you can program) while it is in the product being cooked. Once the cooking process is over, the data logger gets recovered and the data is then downloaded to a software package. The data logger opens up and attaches to a computer via mini USB port. The one that I have used most recent costed ~ $500 US. Price will be dependent on accuracy required and the type of application that you need. If you search the Internet for Data Loggers, you will see many choices available. Hope this helps. 

 

Temperature requirements/specification as yet unfortunately remain unknown.

[Scampi]

coffee is roasted between 350 and 600 F

[Charles.C]

coffee is roasted between 350 and 600 F

 

If so, something like this would presumably work -

 

https://topac.com/thermoprobe.html

[Scampi]

Assuming it's in constant contact with the walls of the bean kettle while they are being stirred

[Charles.C]

Assuming it's in constant contact with the walls of the bean kettle while they are being stirred

 

After a little reading, it appears that depending on design at least three different positions are sometimes used to monitor the temperature of roasting process.

 

Nowadays, there are many types of coffee roasting technologies. Taking into account roasting techniques, coffee beans are conventionally roasted in batch or in continuous systems. The heat can be transferred to the beans by conduction at direct contact with hot metal surfaces, by free or forced convection due to a streaming media (hot air), or by radiation (Wang & Lim, 2014). The most common type of coffee roaster available for home and industrial use is drum roaster. It is a rotating horizontal cylinder that roasts coffee beans placed inside it by continually rotating and heating them by hot air pumped through either the center of the cylinder or through its perforated sides to ensure an even roast.

https://www.proquest...view/2463543183

 

 

Assuming the OP's unit is drum type, the temperature dial on such seemingly, usually, "targets/estimates" the drum surface temperature although the precise method for doing this (and consequently the reading) can vary somewhat. .

 

Both thermocouples and thermistors (max ca 250degC) are feasible (varying accuracies) but  the forrmer (higher temperature-capability) is recommended -

 

https://perfectdaily...-on-using-them/

 

So, assuming the external dial is connected to a single internal TC probe, the tip of latter would presumably be the ideal area to locate a reference (calibrated)  probe of a data logger for monitoring purposes if access available. If no access the type discussed in Post 5 is a possibility.

 

Attachment shows example of a datalogger used for a coffee roaster -

 

 Maintaining_a_Coffee_Roasting_Temperature_Profile.pdf   362.65KB   30 downloads

 

PS - @Kate - So what Kind of a System is it ?

[moskito]

Hi,

 

I have no experience in coffee roasting, but I have performed validation on nuts/peanuts/almonds roasting on different type of roasters (drum, belt). The target is different because nut roasting is done for taste and pathogen reduction. Good description of procedures you will find in literature e.g. via almond board.

What you need in any case beside temperature device(s) installed in the machine itself are independent calibrated temperature probes measuring at different points in the equipment (air, surface and the most important in the product at worst case position).

 

Rgds

moskito

[Charles.C]

Hi,

 

I have no experience in coffee roasting, but I have performed validation on nuts/peanuts/almonds roasting on different type of roasters (drum, belt). The target is different because nut roasting is done for taste and pathogen reduction. Good description of procedures you will find in literature e.g. via almond board.

What you need in any case beside temperature device(s) installed in the machine itself are independent calibrated temperature probes measuring at different points in the equipment (air, surface and the most important in the product at worst case position).

 

Rgds

moskito

 

Hi moskito,

 

My coffee experience similar to your own but I think the detailed analysis for  "worst case" aspect may be specific to the achievement of nut pasteurization. The roasting process will obviously involve such variations if significant but the approaches used seem to be rather more "intuitive". May relate to production volume of course.

Edited by Charles.C, 03 July 2021 - 08:26 PM.
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