Key Indicators of Roasting Coffee

WOLFF WEEKLY VLOGG 018 | Peter Wolff with Key Indicators of Roasting Coffee
Hello everyone, my name is Peter Wolff and thank you for joining in again with us today. I got an email just recently, and they wanted me to outline what it is we use in this roastery to measure I guess the performance, or a benchmark of our roasted coffee. So we do a couple of different things here, and I’ll explain what they are and I’ll also talk about some other general ideas or concepts.
I guess the first thing is keeping really accurate roasting logs that help with not only the time, the end temperature of your roast, that’s very, very important. Keeping those logs really accurate is really important.
One of the things we also use, similar to what we do with the green density, is measure the roasted density. So we go back to the old waterpipe here and it’s a volumetric measurement that we use. It is a little bit difficult initially to start with because the numbers don’t really mean anything until you start cupping your coffee and you start getting an understanding of what does 380g a litre mean to my single origin or blend when I’m tasting it versus say 352 grams per litre.
And so what the roasted density number really mean is the lower the number you go - so if you’re at 350 grams per litre - that would indicate it’s a really heavy roast, so the roast colour is quite dark or it could also indicate it’s a really long roast. This higher the number is could mean one of two things. So if you’re at 380 grams per litre it’s going to mean either the temperature at time has been a bit light. It could indicate the time has been a bit shorter than expected and you get a heavier number. It could point towards underdeveloped flavours and you might start to get grassyness, a little bit watery or thin, maybe a bit of metallic bitterness coming into the coffee.
So from our point of view we run from between 360 grams and 380 grams a litre as a benchmark for our espresso blends and for our filter coffee we would be running from about 390 to 415 grams per litre and that is very origin dependent. But I guess the key thing is once you find the coffee experience that you like from a particular origin then that number relates to that. So the beauty of this system is that as you finish your roast and you’ve cooled it down, you put a sample in the pipe, you weigh it and straight away you know whether you’ve hit or missed on that particular coffee.
Other things that you can be looking at is obviously colour measurement, and there’s a variety of different brands available for that whether it’s agtron, javalytics, Probat’s colouret… there’s a number of different colour measurement tools out there that one can be using.
Another simple guide that you can be using is simple weight loss. So for every one kilogram of green coffee that you’re using, what are you netting out at the other end in terms of loss? Are you getting 800g, which would indicate a 20% roasting density loss? So the range that you would be looking for that’s acceptable would be between 16 and 20 percent. They are very broad averages, but it is something that you can start looking towards using as a performance benchmark.
Definitely I think time is a very key thing - so managing how long the coffee spends in the roaster. In our business there are key three areas that we measure in terms of our monitoring software that we have, our control software that we have. We measure from start to the commencement of the maillard phase. We measure from the commencement of the maillard phase from when it gets to yellow, and then from yellow to cinnamon and then from cinnamon to the end of the roast time. We’re measuring what percentage of the total roast time is spent in these areas. These are areas that we continue to focus on.
So they are just a couple of strategies that one can use in your business to help your roasting team get more consistent and then also putting some quality measure into your business. I’ll see you next week.

[@risdiansah21]

Hi Peter...great videos! I have questions:
• "understanding of what does 380g a litre mean to my single origin or blend when I’m tasting it versus say 352 grams per litre." i'm not 100% understand...Hopefully you come up with a video to explain more detail about this....maybe with a sample case?
• From what i've learn from the roasting class, the density bean is to help us determine how high or low the temperature when you about to start roasting. I'm still not 100% sure what the density measurement is for. Is it to determine the starting temperature or have other purpose. Hopefully you can explain more :)
Many thanks :)

[@WolffCoffeeRoasters]

hi there! in an upcoming question time VLOGG with Peter, he answers this. Thanks for posting the question :)

[@asianbarista]

That's an amazing Roast plan sheet. Where can I get a copy of that?!

[@WolffCoffeeRoasters]

There's plenty on-line! :)

[@djwhouse]

Degrees per minute ROR... Centigrade or Fahrenheit?

[@jamesiskandar2407]

Hello Peter!
Great video!
Will you have the roasting template be available for download? I think it will help us viewers a lot.
Thank you!

[@travelalonekako1422]

🐕🐕🐶