Calculating DTR

Intense Coffee · January 2015

There has been some discussions online regarding Roast Development Time (DT) and suggestions that it should be considered in terms of a ratio of total Roast time (DTR), (as apposed to say targeting around 3 mins only), and that trying to target a ratio for DTR of between 20%-25% appears to produce good results in the cup. This seems to work for the way I roast, and I believe it has improved my roasting. This may of course not suit everyone, and would depend on your ultimate target requirements etc. so please take that into consideration.

I have attached the following Excel Workbook (zipped) in case anyone finds it useful for determining a Target DTR based on the First Crack Time. Set the First Crack Time Minutes and Seconds using the scroll bars and it will calculate a set of DTR %s and Drop Time within the range.

In case you find it useful.

Comments welcome.

cosmic_couple22 · January 2015

Very cool works a treat, bit of Rao thinking behind it I presume? Since your good with excel how about a ROR table put in your drop temp/bottom out temp then select ROR to 155c (drying) 2nd calc.ROR to FC then slide onto the development calc. you have already done. Full roast design based on ROR and % of development Perfect

Chester

Intense Coffee · January 2015

Hi Chester, Give the attached 1st pass "Roast Designer" a whirl. Still need to carry out better checking of my calcs etc, but is this along the lines you were thinking? Graham

cosmic_couple22 · January 2015

Great job Graham, as a first draft I think you have done a splendid job. Had a quick look through and play around and all seems to integrate well, didn't check the numbers extensively but appear to be right. Maybe a little bit of formatting for a cleaner interface but that is always subjective, (those new to roasting might balk at first glance) Tremendous effort Graham, wasn't expecting to see that for a little while after our email conversation.

You have to come and visit the home roastery and have some brews. Thanks again Chester

Intense Coffee · January 2015

Fair enuff re the "User Interface" needing work, I was initially more interested in the calcs and that it was along the lines suggested. I can clean up the "UI" if people think it is useful. Any other feedback/comments welcome from yourself and others before I make any more changes. Graham

cosmic_couple22 · January 2015

I think it is a great tool for planning a roast and giving the roaster another aid as to the progression of a roast and some benchmark figures to help keep on track. For those new to roasting it will help them recognise they need to add or reduce heat/air to keep close to the time values. Again for those that aren't using monitoring software or temp tools and only using visual and audible references it paints a guide map. Now since we developed such a great thing Graham how are we going to market it and make a fortune

Chester

Intense Coffee · January 2015

on 1420530975:

Now since we developed such a great thing Graham how are we going to market it and make a fortune Chester

Pretty it up and turn into a smartphone App ;-) Graham

cosmic_couple22 · January 2015

Did some testing on this today and is looking pretty fine, the numbers were pretty close over the three roasts that I planned out using it as a guide tool. Very easy to use and paints a great picture of the expected profile. To be within seconds and only a couple of degrees of my CoffeeSweet software at all benchmarks was excellent (this isn't doing complex calcs recognising moisture, humidity etc which all has an effect on a stable ROR) Entering turn point etc on the fly was simple and if I had a bigger or second screen having both windows open together having profile software ad roast designer side by side would be great. (switching between windows and entering data and making small gas/air tweaks is a little trickier but doable and would get used to using it this way) A clean up of the interface and quantify all the numbers = great tool for roasters. Blend it all with your sensory skills and it cements what you know is happening and gives extra values to recognise critical points of change so if you want to make changes to your profile for a specific result it lessens even more the hit and miss factor. You can have to much data if it takes you away from sensory skills but I think this is a nice tool too add beside any software you are running and helps hone those sensory things if used wisely. Hope I'm not talking babble, it all makes sense in my head. Chester

Intense Coffee · January 2015

on 1420609852:

A clean up of the interface and quantify all the numbers = great tool for roasters. Blend it all with your sensory skills and it cements what you know is happening and gives extra values to recognise critical points of change so if you want to make changes to your profile for a specific result it lessens even more the hit and miss factor. Chester

Sounds good Chester, I verified against a couple of my roasts, and it came close although not exact. I had a look at the calcs, and refined the ROR slightly to allow a decimal point rather than only whole number d/m. Adds a bit of extra scrolling. So hopefully my calcs are all correct, and do not blow out at some unplanned for usage, and the various limits are within useful ranges. I reckon its probably good enough to get within reasonable limits, the rest will require some common (roasting) sense. But mainly I have tarted up the User Interface to make it (hopefully) easier to understand and use. It's a bit busy and possibly over the top once you have used it a couple of times, but it should hopefully be easier to use for 1st timers. If needed because someone does not have or use Excel, I can convert it into Flash, but that will take a bit of work, and will only do so if there is a demand. If anyone else finds it useful and/or finds problems with it - then feel to provide feedback. Roast Designer V3 attached: Regards, Graham

cosmic_couple22 · January 2015

Great job Graham The guide notes for a beginner roaster are exceptional, a great tool that will definitely help the newbies to grasp what is happening during the roast process. Others will use it as a planning tool and reference point. Now to turn it into a phone app and make a return, today the coffee forum tomorrow the world. Much applause and awards to you (if only I had emoticons still working) Thanks for your effort Chester

Brett H · January 2015

This is phenomenal! You guys have unpacked the rubric that is roasting in a concrete sequential manner and made it easily repeatable. Moreover anyone new to roasting will get a brilliant roast-development overview graphically represented in a very readable format. Congratulations!

cosmic_couple22 · January 2015

It's pretty good BrettH, amazing what happens when a good idea is blended with someone that has the skill to bring that idea into fruition. Hope more people grasp how great a tool this actually is. Chester

Lacehim · January 2015

Have you tried in Open Office? If people don't have MS Office they can easily download Open Office for free. PS. Not that I understand what your all on about. lol. I only have a KKTO struggling along with my 600gm roasts.

cosmic_couple22 · January 2015

That's the beauty of this, will work with anything. If you know your equipment you can make a roast plan based on basic knowledge of how a particular bean acts, end of dry will be around 155 which you can identify by a colour change, sugars will be caramelising along the way where you will reach FC (audible reference) typically between 185-195 in most instances, so slow or speed up your roast (raise/ lower heat setting) to achieve time values based on the plan. Burp your roast at rolling first crack drop some heat and again use the DTR minute value to reach desired development percentage. To assist this do up an excel spread sheet and record your sensory evaluation of the roast every few minutes which helps teach you repeatable visual indicators supported with a time value, giving you a reference next time you roast the same bean and any adjustments can easily be made to meet your plan. (You may kill a couple batches as you build that log but still gives you references that you know didn't work and can change next time) If you are running a temperature monitor, record temps (excel spread sheet) manually every 30sec to 1min with a sensory note recorded every 3 mins or bean change, again giving you a reference next time you roast the same bean. Once you have a small log of roasts as references you will easily make changes or be more repeatable based on the time values and corresponding sensory skills you have recorded. Your sensory skills will also improve as you recognise all the things you are doing and recording have a direct relationship to each other. A little bit of learning and you will be all over it and take your roasting to another level and be able to plan your roast using the designer and hit all the benchmarks at the time value. Let the force flow through you

If i'm not making sense I apologise and we can chat about it when you come for a brew. Chester

Dry_bean. · January 2015

Hmmmm, not sure what I'm missing here people! I've been roasting in a corretto using a DMM for almost 10 years with excellent results. Read through this thread and all I can see is another level of complexity, guaranteed to confuse the heck out of newcomers to the hobby/interest. Perhaps I'm simply not getting the point.

cosmic_couple22 · January 2015

Have to disagree with you on this one Dry bean (not sure that's happened before

) It is actually a very simple tool (have you downloaded it?) lot of science and testing out there these days supporting rate of rise prior to FC and roast development time post FC are far more critical than the FC time itself. William Boot did a study of a few top roasters who used sensory skills alone and on testing they were not as repeatable as they thought they were. This tool just gives a base line in a time value of where your roast should be, which you can then quantify that by your sensory skill and or temp monitor. Would think it was very helpful to new roasters as little understanding is needed to get the values which are known to give at worst very reasonable results. The proof is in the cup I know and I am sure that the cup would support our thinking. Chester

Dry_bean. · January 2015

G'Day Chester, We'll agree to disagree on this one. Guess some of us prefer the Heston Blumenthal approach, others like myself prefer the Antonio Carluccio school. I also used data logging software in my early days of roasting, didn't find it particularly useful either, in fact if anything just another complication, nowadays a watch, DMM, and my eyes serve me pretty well. Your right the proof is in the cup, and I'm pretty certain what ends up in my cup supports my viewpoint. Yes, I did download the spread sheet and checked it out, good job well done, I'm sure many will use it. :-)

Intense Coffee · January 2015

I have attached a Flash version to this post for those that prefer not to use Excel. Its also a less cluttered interface. Just double click the file and it should start in a browser providing you have Flash installed. Resize the browser as required. Graham

Lacehim · January 2015

Ok. thanks for explaining it all. It sounds interested. I've only got back into roasting a few weeks ago but I fly by the seat of my pants when I roast. Consistency! You what? I use a KKTO, with a Turbo Oven. It will roast 600gm to SC in around 22 mins. I don't use a probe, I just put it on full blast, roast until I hear FC, leave it for a minute and either let out some heat or turn it down for a few mins, then back on full. Usually I only roast 300gm, and do 2 different beans because the 600gm just feels like it's not happening right. If this spreadsheet thingy will work with that roasting style then I'll give it ago.

I usually load it all in and go make coffee, relax, read a book on the kindle near the roaster. Maybe I'm too relaxed, but when I first started out it was stuffing it up, and Anger Management and KK told me to relax, and well it worked.

I ditched the probe temp thing early on because it was useless. If you moved it even slightly it crapped itself.

Your probably thinking, OMG that guys roast coffee that way! No way! hahahahhahha.

Intense Coffee · January 2015

If its working for you as is Lacehim, then probably no reason to change to be honest. Might be interesting checking if your Dev Time, (btw FC & Drop) are within the 20%-25% range, as you may be hitting the mark anyway just through common sense. I've always used a monitor of some degree because they came fitted, and its possibly easier with drum roasters so always had these measures around. I'm just now doing more with them to see if it makes any difference. Bottom line is I reckon you can make it as easy or complicated as you wish, but enjoying it is key. I spent a morning with a guy who does it for a living, and he charged the roaster (old 10kg HG), to its capacity, then we went off and had a coffee and a chat. He had no monitoring of any kind. After a while we came back and finished it off and dropped the beans. They looked perfect and his coffee is excellent. Much the same about making a "cup of coffee" I tend to think many of the posts over-engineer that on these websites in my opinion. Horses for Courses. Graham

Intense Coffee · January 2015

Found a small problem in V3.1 of the Flash Model, so V3.2 attached Graham

ash · January 2015

Nice tool Graham. I'll give it a go over the next few weeks and see what the coffee is like :-) Looking through all the versions you've made, I like the second version for it's simplicity. It'll be interesting to see how it fits on the screen of my tablet! It kind of reinforces some things that I've been discovering myself with my roasting.

Brett H · January 2015

on 1420925374:

It kind of reinforces some things that I've been discovering myself with my roasting.

There it is guys... A huge pat on the back for your efforts

Intense Coffee · January 2015

Latest V4 (Flash) - - Also allows the use of Fahrenheit inputs - 2 files now provided - call the .html file to standardise the frame it runs in - Some of the setting limits were incorrect Graham

ash · January 2015

Quick question to clarify something for me Graham, are all the times used throughout based from when the beans are dumped into the roaster?

Intense Coffee · January 2015

on 1421534479:

are all the times used throughout based from when the beans are dumped into the roaster?

Hi Ash, The Drying End, FC and Drop times are based on that yes. So basically it uses the TP Time to calculate the time back to zero, with the key time points being the elapsed time since the Charge point (when the beans are dumped into the roaster), which is considered the zero point 00:00. The "DT" figures in the table refer to the Development period time, which is between the start of FC and the Drop Point. (Note: The start of FC I deem as the moment I hear more than one or two isolated cracks.) This is all predicated on a Drum style roast where the drum is pre-heated. If you use a different arrangement, e.g. The container is not pre-heated and the beans & it are heated simultaneously, then you may need to adjust the TP time to accommodate that, so the 00:00 point fits with your arrangements. I have actually no experience with alternative roasters such as Corretto, KKTO or Popper styles, so anyone who does could maybe provide some advice on how that scenario could be better managed. Oops sorry about double entry, cant find a way to delete one of them. See the following for an article by Scott Rao : http://dailycoffeenews.com/2014/08/12/roast-development-time-and-the-prerequisite-for-any-successful-roast/ Hope that helps. Graham

ash · January 2015

Cheers Graham!

I'm using a Hottop 'B' with a bean temp probe for my roasting, so no help with the other styles of roasters and feed back. I'm using your software along with the CS Roast Monitor Software at the moment, to help me get a feel for the ROC and times. I'm inputing the predicted values from previous roast profiles into your software, then updating it in realtime as things progress. Hopefully this will give me a more accurate DTR value which I use to see where I end up with a drop value. My first batch should have rested enough, after using this process, later this week. So I'll be able to post some results next weekend. The few roasts I've done so far all look quite nice

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