Sweet Maria’s Roasted Coffee Color Card

We created this card as an inexpensive tool to help determine the degree of roast.

Trying to match up the terms we use for roasted coffee with the appearance of your own roast results can be hard! What exactly is the difference between City and Full City? When does first crack happen in terms of roast color?

This card might be a good tool to help answer some of those questions. Looking at roast color alone has it’s limitations. In fact, using all your senses when roasting is the best way, along with some good roast notes and temperature measurement. And, when you taste the resulting roast, relating that back to your roast notes really helps refine the craft!

In any case, having a color reference card to keep by you as you roast, or to check the roast results later using ground coffee samples, is not a bad thing at all. For $2 in particular! You receive 2 copies of the card with each order, with an envelope printed with some handy tips.

The back of our card has handy reference photos of whole bean coffee, using the SCA roast color number scale and approximate roast temperatures. We don’t use those SCA Specialty Scale degree of roast numbers in our reviews, but they are an industry standard. Most electronic devices used to measure roast color use this scale of numbers.

(UPDATE Jan 30: Our latest version of the card adds weight-loss percentage for each level of roast. Weight loss is a great way to cross check the roast color. More info below…)

In any case, color analysis equipment can cost $300 on the lowest end, and the usual devices large roasters use is about $3000! We wanted to come up with a low cost color reference card people could use as a standard to compare roasts.

Other such printed reference materials exist printed using more exacting methods (SCA roast discs, Roastrite color chips) … but they cost tens to hundreds of dollars. We think $2 is better! Thompson created this video to go into some greater details, and the pros and cons of our card.


V.4 Roast Card Now with Weight Loss Percentage

Our latest version of the card adds weight-loss percentage for each level of roast. Weight loss is a great way to cross check the roast color. We tested weight loss for home roasters, both air roast and drum roast type, and averaged them to derive our weight loss standards for each roast level. (They were not that different actually).

To accurately check weight loss, you need a decent gram scale. Weigh your batch before and after (it’s important not to miss a single bean when doing so!). To covert weight loss to a percentage, use this formula: (Green Weight – Roasted Weight) / Green Weight * 100 = Weight Loss %. So if I start with 95 grams, and end up with 85 grams, then 95-85 is 10, divided by 95 is .1052, and times 100 = 10.52% weight loss. Got it?

In case you bought an earlier version of the card, you can pen in these values for weight loss:

1st CrackCity-CityCity+Full CityFull City+FrenchBurnt
412 f418 f425 f432 f438 f442 f448 f455+ f
– 10.3%– 11.5%-12.7%-13.3%-14.5%-15.1%-15.6%-16.6+%
Weight Loss during home roasting depending on degree of roast.

Additional Card Images and Details

Tips to Use the Sweet Maria’s Roasted Coffee Color Card

  • The matte paper and low contrast on the front of the card is intentional.
  • Even with the matte paper, the card can produce a lot of glare. To avoid glare, view card at 20° angle.
  • The numbers and border on the front of the card are 18% neutral gray.
  • The card can take fingerprints easily, so hold by the edges if you can. It’s also part of why we include 2 copies!
  • Ground coffee samples can be easier to judge than whole bean. 
  • Coffee color varies by process, variety and other aspects! So this kind of card isn’t infallible. (nice double negative!)
  • The chaff in bean or ground coffee changes color perception. If a ground sample has a lot of chaff it’s good to take that into account.
  • Weight loss % is averaged from drum and air type roasts
  • Weight loss formula : (Green weight – Roasted weight) / Green weight x 100 = % weight loss

20 Responses

  1. Great idea.I just looked at the price of those coffee color meters and the one I looked at was north of 650$.So the color card is more in line for me as a home roaster. I will be ordering one from you on my next order.

  2. Great video and article! Your writing on weight loss really piqued my interest as I’ve been keeping track of my roasting weight loss since 2013, but had no idea how to correlate the percentages to roast levels.
    Thank you for all the information!
    A side note; all of my roasting has been done with Behmore roasters, the newest one a Behmore 1600 Plus purchased from Sweet Maria’s in October of 2015.

  3. “Weight loss % is averaged from drum and air type roasts”

    Which of drum or air roasts to same roast degree has less ‘roast loss’? Is there an ‘about’ +/- range that makes the average?

    1. The ranges we found when checking different roast processes was really small. Drum and air roasts were (a bit surprising to me) really similar in weight loss for similar degrees of roast. The weight loss difference between processes was .1% – .2%. I think one was .3%. I would expect air roasting to have slightly less weight loss, but it didn’t seem to be the case.

      The larger variable in the process was simply the visual comparison of roast color in the ground coffee. We roasted different origins, varieties and processes (dry-processed, wet processed etc) and there can be small differences in the way those coffees color in different roasters. Of course, end of the day, you want to be comparing the expected roast taste in the cup, and produce some meaningful relationship between that and the weight loss / roast color. The core reason anyone would use this info card is to try to reproduce the roast level they like, or have some guide to know where their roast ended up, even if they don’t like the results!

  4. Thank you, Tom…

    I was going to ask more after your response. I’ve decided to not. I will say, though, if it ever strikes you to continue on into the vagaries of roast lost… water and/or physical body… loss changes for initial moisture content and/or other conditions effecting… I would be very happy to read it.

  5. That would be fun…

    Just to say… my interest in roast loss came from ??? where it was implied a person could roast a bean to same roast degree with more or less roast loss and that same-bean with less roast loss for same degree of roast had ‘more flavor’. I’ve never found another similar reference, but then, a person doesn’t find much on roast loss.

    I suppose, given the lack of roast loss information, maybe all that it is is a measure of the degree.

  6. Hello,

    The card look great and quite interesting. I am wondering if you are planning to make a version in celcius? If not maybe just add it on this webpage so that anyone interested in the celcius temp can write it on their card?

    Regards,
    Patrick

  7. Are the weight loss percentages applicable to dry process beans? By percentage (8.8%) these beans are barely roasted.

    1. Yes it should apply well to any process. I agree 8.8% would be very light. When measuring a small batch roast, every bean counts. Losing even a few beans can throw off the % . Just a possible explanation.

  8. I’ve been measuring green and roasted weights (and volumes) for a decade, most of the time roasting 1/2 to 3/4 lb lots in a Behmor 1600/1600+. I have generally found a reasonable agreement between the weight loss and other clues (color, snaps, time), but the weight losses I measure have always been larger than your numbers. For example, this evening I roasted the last of the 2021 Xinabajul Punta del Cerro to what I would call an FC finish. There might have been a few eager snaps, but those could have been lagging pops – there seemed to be a lot of lighter beans when it was sorted. So 332g in, 279g out, which is 15.96%, but I can assure these beans weren’t burnt! There were a few beans that dropped into the tray, and one porcupine stuck in the drum wall, but those can’t total more than 1g (if that, the drops were smaller beans, maybe fragments), and 1g only changes it to 15.66%

    And as I say, this is in line with most if not all of a decade of roasting in the Behmors, so I really can’t make sense of the numbers on your card. 🙁

    I have seen, almost often enough to claim it’s a real effect, roasts of the same lot to the same finish (as near as I can judge) but with different total roast times, mostly due to line voltage differences. And what I believe I’ve observed is that longer roast and (slightly) higher weight loss go together. In keeping with this, I ought to mention that 300-ish gram batches usually run around 15:00 here. Half pound roasts do run faster, but they run down to empty jars faster, too, and make for a less convenient roasting schedule. 🙁

  9. Hi Martin – yes I can definitely see how you will get numbers in that range for a roaster like the Behmor, and we have heard that from a couple other people. We averaged weight loss between air and drum roasters to come up with the numbers on the card. But even with larger shop roasters, I can tell you there is a big variation. I used to roast on a Diedrich where I anticipated 15% weight loss on a Full City + roast and switched to a Probat where I was getting 18% for the same roast. I’ll also add that the smaller the batch, the more the loss of even a few beans throws the percentage weight loss. It does add up. Anyway, it is hard to make a “one-size-fits-all” card that is supposed to have real data but then ends up having to “ballpark average” a few things. Maybe we should make a Behmor version?

    1. Agreed with the above. All of my last roasts on my 1600+ range from 13-16.75% and im pretty much always in the C+ to FC/FC+ on all roasts… so.. would be cool to see a behmor card for sure!

  10. Does it matter how large the order I add the card to is? As I’m based in Europe, ordering from the US comes with import duties, which could make an order quite expensive. I would really like to have this card, as I think it’s a fantastic tool, but I do want to keep things within budget.

    1. There is no order minimum Erik! You should be able to generate a shipping quote once you’ve added the card to the shopping cart. Feel free to reach out to us if you have any issues placing the order – [email protected].

      Best,
      Dan

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Related Posts