Why does my roast color look so uneven? Home coffee roasting issues

good morning I'm Tom at Sweet Maria's Coffee and I'm going to talk today about evenness of roasts that means the surface appearance of coffee that you roast you have one batch that bean to Bean has a very even brown color and you have a batch where you have a lot of variation in the surface color of the coffee specifically I'm going to address natural coffee what I've done is roasted four batches here in different Roasters of the same natural dry processed coffee so this all started because yesterday we had a kind of spontaneous conversation downstairs because Chris had roasted a coffee it's our Ethiopian adido desolenicho natural dry processed coffee in the bullet roaster and got this very even surface appearance and Eric had roasted the same coffee in the fresh roast sr800 kind of a faster air roast and had gotten a very uneven appearance and we tasted the two coffees and they were certainly different but the questions came up like is it the roaster is it the coffee why the same coffee could produce two different appearances and so I wanted to break apart this pull apart this issue of the appearance of natural coffees that you might roast but it's quite complicated when I do so and I don't really have all the answers to this I have to admit a lot of What You observe is kind of anecdotal but after 30 years of roasting you have some observations from it so let's sort of take this apart and the first thing to that I'm going to have to set aside is the level of roast so if you roast coffee darker it just tends to develop into a more even dark brown color and you'll have a more pleasing even appearance maybe some oils will migrate to the surface and even some of the the coffee that would not color brown in the lighter roast will kind of brown as it gets to the really dark levels so I have to kind of set that aside as an issue because these are all the same roast level um more or less and they're all sort of city level roast medium roast I checked that roast color really with the ground coffee sample that I set up and put next to each other so I don't really look at the variability of the surface appearance from Bean to Bean in the roast to do that um so that's the first thing to set aside the second thing is the coffee and the third is the roaster so in this case we're talking about natural coffees because these tend to be the ones that don't roast to such an even surface appearance now what's that about well as far as coffee from the tree when it's harvested it's impossible to pick only the red coffee cherries you're going to get some that are partially ripe with green more near the stem and red on the tip and you're going to get some that are fully green they're just going to come off as you selectively pick now super uneven roasts are something that traditionally has belonged to commercial coffees and to low-grade coffees for example in Naturals there was a designation Jima grade 5 natural and those coffees just the labor that went into them is a lot different than high-end specialty coffee Jima grade 5 would be tend to be picked more indiscriminately the coffee comes into the drying station or is laid out in the farmers home or backyard and there really isn't hand selection specialty coffee there's rigorous hand selection the beds are laid out and they're gone over time and time again to remove the green coffee Cherry now the fully green unripe coffee Cherry is what results in what we call a Quaker in the cup a Quaker is a being that just resists roasting it that's which is not really a true term it resists turning brown and then you have semi-quakers which are sort of those partially ripe coffees those can result in a Martin color uh from experience uh observing it and then you have the ripe cherries which should Brown normally what's that about so unripe coffee Cherry green coffee Cherry that has not fully developed as a seed and a fruit doesn't have the same chemical compounds that are precursors to the Browning reaction that happens during roasting the maillard reaction so they simply don't have the material in them to turn brown and so that's why they appear not to roast they do roast they just don't Brown like ripe coffee cherry and In Those Old School Dry process you would see a lot of that so the fact is though even in some really high-end natural coffees you're going to still see an occasional Quaker and semi-quaker because it's incredibly hard to find those especially once the coffee's been on the bed for let's say a week and it starts to go from red to Brown they're harder to distinguish that's why a lot of stations we work with are very focused on getting the green coffee the brightest green coffee out immediately before it turns brown and you can't tell it apart as well so one of the main things that's come up as I try to take this small conversation we add downstairs and turn it into something meaningful and fairly thorough is that we're talking not about even roasts we're talking about even roast color and I've already suggested that right but even rose color is not even roast and I just want to show you this because here is on the bottom row is the fresh roast a range and what I've done is I've chosen about four beans here up to about here five let's call it that represent the range of the roast which is this is the rest okay and on the top row is the bullet and this is the roast okay so and so these represent a you know sort of well-browned coffee visually even roasted coffee uh within a certain range and then we get into these things that start things that visibly you would call Quaker semi-quaker and it's it's hard because on the phone camera I can tell you that in person these really are marginally semi-quaker but what my experience has been and it's been heightened by this test is that things here that would start to look like a Quaker let's say here and here this when I do my little impromptu taste test this is quite a nice sweet coffee then we start into getting some popcorn type flavors here definitely Quaker this had this Bean looks like it has another problem but um absolutely a Quaker totally a Quaker 100 percent gonna be a peanut type Quaker probably popcorn Quaker um don't know about that one let's skip that one so the strange experience here and I know this is not a great science in any way but it's just purely anecdotal is that I'm actually getting those peanut flavors from Beans like this and popcorn flavors and beans like this even though they are in a different sort of range of brownness that over here would be you know quite uh quite par for the course with ripe coffee so sorry this is Ethiopian wet process this is Ethiopian dry process and you see the color of the remaining silver skin which comes off the bean as chaff as the chaff component and you see how different they are and this is something that really changes our perception uh of evenness um and also roast level another thing that really influences our perception of evenness is silver skin itself so these are instances where in in roasting just depending on the roaster you'll get a lot of silver skin removal from the way the beans are agitated all of these as you can see have remaining silver skin which is a continuity with the silver skin that's in the fold silver skin that's in the fold doesn't like to come off the silver skin that's on the outside usually comes off in this case it doesn't and all of these were pulled from arrows the drum roaster had pretty much hundred percent I couldn't find an example let me see here's one right here a little piece there now let me do of course another saturated test and so I was just doing Plumbing we had a pipe burst well we were cleaning and we broke a pipe believe it or not so what what you can see here and I'm just putting these beans back is quite well roasted coffee under something that visibly looked very uneven so the other issue now just just to be clear on this is that silver skin on Naturals tends to darken and I think that's probably a lot be about the fermentation the contact time with the mucilage inside the Cherry as it dries and it stains white that stains dark or colors visibly darker but that silver skin is still there I can see it and the white silver skin is much more visually apparent so all this talk about visible evenness of roast leads us back to the green coffee and as you can see this is what we typically think of as as actual green coffee that's a Columbia wet process and this is the coffee we're talking about this Ethiopian natural so they tend to look more yellow this tends to be from the fact that there's more silver skin on the coffee seed and that the silver skin has a yellow Hue to it probably from a long contact time fermentation time inside the Cherry yes natural coffee is fermented it's not fermented in a tank it's fermented in the fruit but the same mechanisms of fermentation are occurring and the other thing that's unique about this in a big picture is that coffee is this Agricultural Product and it's variable and it comes from the tree and then through the process of selection of the cherry on the tree selection by machines and in a wet Mill or hand selection on a drawing bed in the case of Naturals we are essentially homogenizing the coffee we're homogenizing it with the goal of finding the ripe fruit and the dense seed and the mature fruit and that's the coffee that goes into specialty coffee um the naturals by their nature and by the lack of mechanism in the processing processing are going to be more heterogeneous they're going to have more variation and so in some ways the variation we see in the roast color does go back to what natural coffee is about so I think generally in the consumer side or the coffee roasting side the Importer side we think of coffee a little more mechanically we think of you know 22 second shots on a Nespresso machine and you know 12 minute and 35 second roasts and in a way the agriculture side of coffee doesn't conform to those kind of mechanical mechanistic ideas of something quantifiable by numbers so this is the coffee I just pulled out not even trying um a variety of coffee beans some borderline defect some really not defective at all and all of these are going to be contributing something different to the cup and of course that cup based on you know the 45 beans that may go into making that single cup is going to vary and what you notice here is this incredible range of size these kind of long Berry type varieties some of these are Selections in Ethiopia some of her kind of mother tree heirloom coffees um right here I got excited because I thought I'd found a visible Quaker what will become a quake or an immature seed in a natural coffee it would look green but not like a green washed coffee it would like this oops sorry there's one of our Columbia's it has a kind of metallic silver skin that clings to the surface but you know this kind of disappointed me and now I don't think it actually is a Quaker but that's a sign of a Quaker and and that's so hard to spot just visibly let alone by a machine that it's very hard to like color sort Quakers out of coffee sometimes it can become by density but a lot of times Quakers are actually quite dense beans it's a pea Berry this is a little bit shriveled and here we have coffee here here here and here where you have a lot of a silver skin attached that's quite stained by I guess the fermentation is my best guess and these used to be called foxy beans that's not a joke they were colored and they were considered a partial defect and yet it's really just you know exterior surface color um I did think that one of these might be what you call a sour the sour was was where the coffee is actually had a kind of secondary lung fermentation and that used to be considered a defect too up until quite recently and in some camps it still is but now with you know anaerobic coffees which aren't really anaerobic but that's another thing um you your people are actually trying to create sours um you know and that's legitimized there's sour beers and that's a flavor some people really like it's these intense fruity kind of acetic vinegar sour uh in some coffee so um these may qualify sours but I can't really see the coffee underneath judge that underneath the silver skin okay so let's add in the complicating factor of what type of roaster you're roasting your natural coffee with your dry process coffee so yes my experience generally is that a drum roaster of various kinds will roast to a more even surface appearance drum roasts tend to be long longer roasts arrows tend to be faster roasts they roast because of the hot air stream they tend to do some different things with coffee visually they tend to Puff it more enlarge it more and yes I think you generally will see more variation from being to being in the surface color of coffee now I think this is a false comparison in a way because air roast and drum roast aren't really too clear categories there's all kinds of things in between and what one air roaster is doing versus another let's say a fully fluidized bed air roaster like a civets were some of the home Roasters some of the poppers versus one that's a cyclonic action swirling coffee around those are two really different things and with drum Roasters you have a very old style uh more conduction heat system with a cast metal drum like an old Pro bat it depends on how your airflow and your drum speed is set up and then you have hybrids like the lowering is that a drum roaster an air roaster it's kind of both on the home roasting side you have the gene Cafe that Rose in a drum through a hot Airstream so there's not really a clear category in between one and the other but you know have observed more surface appearance from the longer roasts that are in drum roses versus faster arrows so the next thing is what is that meat does that mean a coffee is good or bad so here I have my comparison of the roast levels from the ground coffee which is more accurate than really looking at the um at the surface of whole bean coffee and then I have my cup and um so the most important thing here that I learned a long time ago from an old coffee Trader is don't cup with your eyes cut with your taste buds and that's really true it's not about what coffee looks like it's about what it tastes like now it doesn't mean it means nothing that if a coffee looks uh really weird or uneven in the roast that you're not going to taste something there's some evidence there about some issue but you should really go primarily by the cut flavor so let's taste these coffees and see foreign went through these when they were a little bit hotter and I'm only producing one cup each which isn't really protocol um there is a lot of clarity and Sweetness in this Rose one thing that may be true is that the person who roasted this which wasn't me might have actually hand-picked out some of the light Quaker beads now with home roasting that's always an option home Roasters have this great advantage of being able to sort of upgrade and improve their roasts that a commercial roaster if you're roasting a whole bag of coffee at a time is very difficult to do some people have looked into color sorting machines after roasting to improve the quality of coffee which is a mixed bag um shouldn't you you know pay for better coffee with money that goes then to the producer side in order to to get the cup you want versus use Tech to improve your coffee potentially you could then buy lower quality coffee and upgrade it for your use yeah I'm a little on the fence about that but home roasting picking out a few Quaker beans is really easy but one of the things to really distinguish is which coffee here is influencing the cup and that's not so clear my I use a a test that is proven in time I just eat the coffee so I find a truly light Quaker Coffee Bean like this one and don't choke because it's easy that shockingly was not that bad of a coffee it has a sweet fruitiness it's a bit honeyed this one definitely has the popcorn kernel flavor you know you eat one of those unpopped popcorn kernels that would distract in the cup but it's not really the super astringent dry like peanuts peanut skins nut skin flavor so that's very interesting on this end of the spectrum where we get a more even roast foreign that didn't appear to be a full-on Quaker but it is kind of popcorn-like the popcorn kernel like that one just has a kind of a dry flavor so I know that you're probably going to be laughing at this great scientific method of eating the coffee chair eating coffee bee but you know a lot of knowledge and coffee um happens anecdotally like this You observe something and you check it and you find out and that also leads you to question things like doesn't even roast taste better than a roast with more variation in the surface color there's also this interesting thing is that when you travel and you visit coffee washing stations and Farms you always want to encourage good even picking coffee the fact is is there's been some experiments in 100 ripe coffee Cherry harvesting like pure red exactly the same color the result at times you don't want to tell all your producers this is that cup has been flatter and less Dynamic and interesting especially uh in terms of the range and sweetness and acidity then coffee with some variation in the ripeness of the fruit again it's an anecdotal experience but you tend to flatten out the flavor when you get too much uniformity in coffee in my experience so should all coffee Cherry look uniformly right I don't think that's necessarily a good thing just based on my experience so in tasting these coffees I do get great clarity and sweetness from the bullet roast but I Feel It suffers a little in terms of dynamic acidity but I do like this cup a lot um in the fresh roast it's actually surprising that this cup does not taste that quakery it has a lot of sweetness has a lot of fruit and sort of dynamic range there's a little bit of a dry biscatiness but it's in no way astringent and that's a little surprising so this is a test that just came out of a conversation we had downstairs and we thought well people would like to understand should I be looking for even roasts is an even roasted good roast why do my Naturals not roast as evenly as some of the wet processed coffees I buy is there a problem with that and ultimately it's going to be up to you to taste the coffees and ask yourself whether you like them or not or whether there is a roast issue or a coffee quality issue to figure out but one thing is if you do have like coffee beans taste them find out what they're contributing to the cup and what we like to do is if we see a roast of like 100 grams with a lot of light coffee we'll call out all of the light beans and we'll create a cup where it's loaded with the the light colored coffee versus one that's darker or and then one that's unsorted and we'll taste the three of them and we'll find out what is this contributing to the cup and the results are oftentimes surprising to us so we have another illustration for you about Naturals and that pretty good lots of natural can have Quakers this one's a little bit of surprising I was just roasting for fun some cup of excellent samples so this is Brazil number five Geisha 90.41 points 1310 meters so the minus here's the green coffee Geisha natural there's a cup of Excellence so you know a lot of people agreed that this was a fantastic cup of coffee over 90 points and yet roasting it on the pro bath did a pretty nice roast oops here's one more and this is what I have just you know estimation of what I think are full Quakers and semi-quakers from this roast and uh things like this are absolutely full on Quaker and like I'll do my test I will taste these and I'll see how strong the astringency whether it's towards peanut and peanut shell that's the real strong one in my opinion versus Popcorn versus something that's just like kind of biscuity but actually sweet and contribute something nice so I'll check these out foreign oh dang well I said that was one of my definite two full Quakers very very quakery very astringent wow let me take a semi semi Quaker popcorn like the unpopped popcorn kernel so I know this is pretty laughable to me eating coffee and tasting but I don't know another way to isolate a single defect one complete unit one bean of defect and get some sensory perception of how strong it is what that contributes to the cup how much it's distracting I don't know 90.41 points so I don't know if somebody called these out before I don't think they're allowed to do that in cup of Excellence but wow that was a really strong Quaker

Channel: Sweet Maria's Coffee

Views: 11,430

Keywords: coffee, sweet maria's, home coffee roasting, green coffee

Id: MfBPhKZbp2Q

Length: 26min 42sec (1602 seconds)

Published: Mon Feb 06 2023