Roasting for Espresso vs. Filter

One of the issues roasters ask me about most frequently has to do with the difference between roasting for filter or espresso. It’s a frustrating topic, not least because I don’t know exactly what others mean by “filter roast” and “espresso roast.”  Most roasters roast darker for espresso, but one roaster’s “filter” may be darker than another roaster’s “espresso” roast; there are no universal definitions.

Years ago a client implied on his blog that I advocate “omniroasting” (i.e. roasting the same for espresso and filter.)  That was an assumption he made because I had asked him why he roasted differently for espresso and filter. To him, my question implied that I believed in omniroasting, but that wasn’t my intention.

I don’t have a strong opinion about omniroasting, but I’d like to share some thoughts and let you draw your own conclusions.   My hunch is that most roasters roast espresso darker because of some combination of these three factors:

  • Temperature
  • Underextraction
  • Milk

 

Temperature

 

When brewing filter coffee, the ratio of water: grounds (by weight) is usually something like 17:1.   When brewing espresso, the water involved in the process (water that gets into the cup + water absorbed by the grounds) relative to grounds is typically 3:1 or 4:1.  Let’s do a back-of-the-envelope calculation:

 

Batch brew:

water: 1700g @ 94° c (201°f)

grounds: 100g @ 25° c (77°f)

If you were to mix the grounds and water together, and the average temperature will be near 90°c. (194°f) (I know this a gross oversimplification of slurry temperature. Please bear with me and focus on the forest, not the trees.)

 

Espresso:

water: 70g @ 94° c (201°f)

grounds:  20g @ 25° c (77°f)

average temperature of the system:  79° c (174°f)

 

Not only is the average temperature much higher in a batch brew, but espresso extraction is much more “front loaded,” meaning a disproportionate amount (>50%) of coffee solids are removed in the first few seconds of an extraction– and, that early extraction happens at a very low temperature, perhaps around 70° c.  When brewing filter, extraction is less front-loaded and early extraction occurs at much higher average temperatures.

 

Hey Rao, does this really matter?

Good question.  When’s the last time you set your kettle temperature to something like 81° c (178°f) for a hand pour?  Probably never, but if you did, what was the result?  I’m guessing the coffee was rather sour.  My point is that the lower temperatures of espresso extraction tend to make coffee sourer.  And to combat sourness, roasters tend to roast darker.

 

Underextraction

 

Before there were VST baskets and the coffee refractometer, espresso underextraction was the norm in specialty cafes.  Poor grind quality (still an issue, though there are finally a few espresso grinders out there able to extract normales above 20%), and the popularity of dosing 18g–20g (into baskets meant to hold 14g) contributed to frequent underextraction.  For several years, third-wave cafes and their predecessors were almost always serving sour, sub-19% espresso extractions.

Underextraction, like low extraction temperatures, often makes coffee sourer.  I believe chronic underextraction contributed to the popularity of roasting darker for espresso than for filter coffee.

 

Milk

 

I’d estimate that more than 80% of espresso shots pulled outside of Italy end up in milk-based drinks. Simply put, most roasters and consumers seem to prefer espresso to be roasted a little darker when it is to be consumed in milk rather than black.

 

Should you roast darker for espresso?

 

If you’re underextracting and combining your espresso with milk, yes, almost certainly.  If you’re confident your extractions are high enough (let’s say >19.5% on most grinders, >20.5 on an EK) to avoid sourness, the answer is not so clear.  Even when roasting for black coffee (ie not combined with milk) to be pulled at a high extraction, there is still the issue of most of the extraction occurring below 80° c, and the potential for sourness.  I assume the extra sourness of such low extraction temperatures would still lead most roasters to prefer slightly darker roasts for espresso than for filter.

 

The More Important Consideration

 

When roasters ask me about roasting for espresso vs. filter, I usually emphasize that whatever my opinion of the issue, it’s more important to focus on whether one should roast differently for black coffee (no milk) vs. white coffee (cappuccino, latte, etc).  To me, the difference in roasting for black vs. white coffee is significant; the difference in roasting for filter vs. espresso is modest.  That delicate, lightly roasted Yirgacheffe that tastes sublime as a straight espresso may drown in a cappuccino.  Likewise, I’ve had delicious cappuccini made from shots I would have found flat or slightly roasty, had they been served black.

 

The Bottom Line

 

Don’t worry too much about omniroasting or other philosophical issues.  Try not to be dogmatic about how light or dark a roast must be, what’s popular, or what you’re “supposed to do.”  Measure often, taste blindly, and try to be logical (ie “if extraction temperature is lower, coffee may taste sourer, so perhaps I should try roasting darker and see if it’s better.”)  In the end, go with what tastes good, even if the internet disagrees or this year’s barista competition finalists did the opposite.  I promise in a year or two the winner will do the opposite of what this year’s winner did!

I’ve only touched upon the surface of this issue, so please share your thoughts.

45 thoughts on “Roasting for Espresso vs. Filter

    • hahahaha.
      You must not have read the other 20 posts where I share my disdain for naturals 🙂

      Seriously, though, my beef with naturals is that as single origins, they have rather boring, monotone flavor profiles. But I’ve enjoyed some espresso blends with judicious (<25%) use of pulped naturals and honeys.

      • No.. but looks like a touched a nerve! But at least you have some love for Naturals, all 25% of it . Boring? I would disagree on that point but I understand why the complexity of washed coffee’s are more suitable to Espresso. I never consider blends but I understand there’s still an appetite for well formulated/roasted blends.

        • Tony,
          I don’t begrudge anyone for liking naturals. Thankfully not everyone is as boring as I am, always seeking Kenyas. If they were, Kenyas would cost $1000/kg and I would have to give up coffee drinking 🙂

          Actually, I think the complexity of washed coffee makes it suitable for filter coffee. I don’t care for naturals, period, but if I had to drink them, I’d rather have them in espresso than in filter. Filter brewing is better suited for bringing out subtlety in coffee.

          • Ok.. I totally agree, Naturals as Espresso, Washed as filter.. That’s my approach to brewing Coffee, but my fellow customers/friends have alternative opinions..
            This is what makes Specialty Coffee so interesting and posts like this so inspiring..

          • I think the fact we refer to naturals as a “natrual flavour” or thinking they have a distinct flavour profile is the real problem. When we refer to a origins flavour profile by default refer to it’s washed process flavour profile. I believe the problem starts at origin, if we (roasters and baristas) help producers understand how to accurately process naturally we’ll start to bridge the gap between washed and natural flavour profiles. Instead of having two very defined flavour characteristics, we’ll have naturals that taste like washed and vice versa, opening a whole new spectrum of flavour. I pray for a day we don’t need to know whether it’s a natural, washed, honey, pulped, semi dried because processing is that good and spend more time focused on sustainability of high scoring coffee.

  1. As a hobbyist roaster I assume, that a darker roast is less sour. But for me it is important to develop the individual aromas of a coffee. So it is clear that some proveniences do better as espresso and some vice versa. For me It is mainly a question of green coffee choice. Moreover one can modulate the result by temperature, ground and dose. So variations are endless.

    • Erhard, I’m a little confused by your comments.

      Variations may be endless, but almost everyone, at least in the industry, would prefer the aromatics of light roasts vs. dark roasts.
      I’m not sure why you say it’s clear that some beans do better as espresso and some as filter.
      And adjusting temperature can help mitigate sourness, but only to a modest degree, before the temperature is high enough to cause acrid and burnt flavors.

  2. Scott – we tend to omniroast, but for milk-based espresso drinks use a bottomless portafilter for (at least psycho-sensorially) higher acidity and more expression in milk. We serve small ceramic at 5.25 oz cups, and reluctantly larges in 9.0 oz ceramics, with 1:1.6 ratio dry:wet (typically 19.7-19.9:32, depending on the origin – we serve SO shots almost exclusively). Our focus tends to be on proper particle size to get the right taste profile between 25-33 seconds (if possible), to tone down acidity on shots, and maintain a nit more acidity for milk-based. What do you think? [Question: is heat sink factor of single spouted portafilter -v- bottomless, higher in the former, thus, a higher output temp in the bottomless, or vice versa?]

    • David,
      I’m not sure I can agree about the difference between bottomless vs. spouted in regards to flavor. Also, at that brewing ratio, it will be awfully hard to not underextract often. Why so short? And why so reluctant to serve 9oz beverages? You’ve got a 19.8g dry dose… that’s 2.5x the typical dose in Italy, where a respectable cappuccino is 5.5oz. So your 9oz drinks are stronger than the typical Italian cappuccino, for what it’s worth (not to say that has to be the standard, it’s just a useful point of comparison)

      If you really want to tone down acidity, lengthen your shots and increase your extractions.

      I’m not sure the heat-sink issue, if there is one, with spouted portafilters is all that significant.

      Honestly, I think too many nit-picky details are being focused on here, and it would be better to step back and look at the big picture:

      -what extraction level tastes best?
      -what dose/bed depth works best in your baskets?
      -what espresso TDS x shot weight creates the balance you seek in your various drinks? (ie a 19g dose may overwhelm a 3oz macchiato but taste great in a 9oz latte)

      Just my two cents.
      Thanks
      Scott

      • Scott – thanks.
        Interesting. I always wondered if it was worth the effort to customize/calibrate each shot for beverage size. It makes sense, but can be tedious, and perhaps executed with a small batallion of grinders? Our Espressos are served in 2.25-2.5 oz ceramic, Macchiatos (in glass) are 2.7, Cortados (in glass) 4.1, small milk-based in ceramic 5.5, larges in ceramic 9.0. So you recommend we have distinct dry:wet ratio and volume for each size to optimize taste and concentration for each. I like it, but on the barista end, perhaps too much? Can you tell me (offline is fine), who is doing this successfully? Thx. Hope to see ya soon.

        • Hi David,
          I’m not recommending customizing for each drink. That sounds great, but may be impractical. I’m just saying that one should consider the two extremes, the latte and the macchiato (for example) when choosing a ground dose for a cafe, and how using the same dose for both can be problematic. (ie if they both use the same dose, either the macchiato is too strong or the latte is too weak) I don’t have an easy answer. Personally, I like the idea of two grinders: one for milk-based drinks with a larger dose and perhaps a slightly darker roast (and maybe 20% pulped natural. haha). The other with a prettier coffee, smaller dose, and used for straight shots and macchiatos. Something like that. I’ve done a version of that before at a very busy cafe, and it’s not difficult to execute well.
          Of course, with truly programmable pressure/flow profiling, things like this will be a lot easier to do well.

  3. To be honest in roasting I do not know what is the right way to follow when roasting for filter or espresso.

    So let me start by saying I have only been roasting for a few years and I roast on a Diedrich 2.5 ir. I have had no real instruction in what is the right way or the wrong way to roast. I have a great mentor who I phone from time to time to bounce ideas off but that’s it. Oh and I have just started to read your book.

    When I roast I do what feels right then test that coffee on the cupping table. When we have found the point of which that particular coffee is full and complete and you step back from the cupping table “Oh yes that’s it we’ve cracked it” I know I have done my job. We then try it on every brew method we can to see what works best for that coffee.

    I think that our job as roasters is to make those coffees we buy sing, so if on the cupping table a coffee is full, well balanced, complete and delicious. So what if it is a dark roast or a light roast as long as you have done your best to show it off, who is to say what is right?

    As you know every coffee has its own specific signature, so maybe you don’t always have to roast darker for espresso, you could be clever and blend your coffees so they make great espresso and also cut through the milk to have great milk-based drinks to.

    Who knows? As I said in the beginning I am new to this and find that as long as we are having fun that is all that matters, I love my job as a roaster it can be frustrating at times but it is also very rewarding.

  4. How does aging the coffee come in play? We have seen that light roasted coffee ( medium to medium dark ) if used after 9-12 days tastes really good and well extracted whereas darker roasts can be used by aging them for as few as 4-5 days. Haven’t really read anything on the relationship between aging and roasting for espresso yet, would love to hear about everyones experiences

    • Hi Ayush,
      Perhaps I’ll write a post about that some time.. .For now, just know that aging coffee helps increase espresso extraction– sometimes a lot– but has a trivial effect on filter and other non-espresso brews.

  5. Holy shit, Scott! Now, I thought you had me spinning many times already but re-reading your literature and concepts helped me settle down. This is right up there, almost like a Monty Python skit: “… move your clothes down onto the lower peg immediately after lunch, before you write your letter home, if you’re not getting your hair cut …” 🙂

    This blog is a well-thought piece, somewhat labyrinthine, but left to us in creative space. George Howell would be proud to join us for a cup here.

  6. Perhaps a very different topic for a different conversation, but… your comments on the difference in slurry temperature between filter preparations and espresso preparations make me wonder how recent thoughts and experimentations on chilling coffee prior to grinding (for the sake of grinding, although not necessarily brewing. The chilled, ground coffee could theoretically be brought back up to temperature after grinding but before brewing) will affect the way we roast coffee, and if it will increase the variance or difference between the way espresso and filter coffee profiles are generated. For example, If we’re starting with room temperature coffee beans, as you mentioned, the liquid espresso’s final temperature is a little lower than batch brew. That difference is magnified when using chilled coffee beans. To make the espresso more readily soluble, given the smaller amount of thermal energy, perhaps we will see an even bigger change in roasting differently for espresso vs. filter. Or maybe the answer is simply, pull longer, hotter shots. Any thoughts?

    • Hi Kyle,
      I’m sure chilling the beans will have many unpredictable effects. But given that I haven’t tried it, it’s too speculative for me to comment on. I would expect pre-warming espresso grounds would have a beneficial impact on flavor, but not sure how one would do that without some unintended, undesirable consequences.

  7. Thank Scott!

    I think it could be helpful that some people really like milk in typically acidic coffees (like me!). I find that the acidity and berry sweetness combines with the milk making it a really caramelly beverage.

    Unfortunately I was denied this at a cafe in Sydney where the barist refused to make me a piccolo on an Ethiopian!

    On the other hand, when I was doing some V60 training, all we had was the house blend to use. Did it taste mind-blowing? Not really. But was it really tasty, yes it was!

    Was listening to Cat and Cloud podcast who simplified the degree of roast to ‘how soluble do you want your coffee to be?’ Thoughts?

    • Hi Michael,
      I have opinions, but when I’m serving customers, I never tell them they can’t have it their way, assuming what they’re asking for is possible. i’ve had countless baristas tell me I couldn’t have what I wanted (a particular bean as espresso or capp, espresso in a to-go cup, etc) and I think it’s both terrible service and misplaced snobbery. Most of those baristas seemed to think they knew better. None of them did.

      I don’t really have a comment about the C&C assertion about degree of roast, as I haven’t heard it in context. But I would prefer that we not muddle definitions. If one roast is far darker on the outside, but far lighter on the inside, than another roast, I’d say the darker roast had a darker “degree of roast” but I wouldn’t know, without brewing, which was more soluble overall.

  8. What are your thoughts on some of the other roast parameters other than degree of darkness for an espresso roast? Any fundamental differences in approach to say, overall roast time, or development time ratio?

    • Hi Brian,
      I guess what I’m trying to say is that there is no “espresso roast”. And I don’t buy into the idea of simply “extending development time” or other simplistic approaches that make coffee taste flat or roasty. Your DTR may be a little longer with a darker roast, but the shape of the curve probably shouldn’t differ much from that of any other roasts you do.

  9. Hey Scott, amazing post. This topic has rattling my brain for quite some time. One question, when you say darker are you directly correlating that with more soluble? I’m not sure if that is a silly question. I mean for espresso I try and make our coffees more soluble, so they are easier to extract. I would like to think i’m doing a good job of making it soluble without going darker. Can you do one without the other?

    • Hi Darren,
      I’m talking about darker overall: inside and out. It’s really, really hard to get much more soluble (overall) on a roast without getting much darker on the outside. At least, I don’t know even a handful of people capable of doing that intentionally and consistently.

      It’s not a silly question 🙂

    • Hi Kirby,
      Unfortunately, Cairns is pretty far from the surf and the part of the ocean in QLD not patrolled by deadly jellyfish and other scary creatures. Not sure i’ll make it there anytime soon :(.

  10. Fascinating as always Scott, I think you’ve managed to explain this very well. I’m not sure I agree with your average temp calculations for two main reasons though:
    i) the ambient temp inside a portafilter is going to be a lot hotter and more stable than inside a batch brew basket
    ii) during service, espresso grinds are usually in a range of 40c-65c and as high as 80c with some grinders.
    In my experience it takes about 12 seconds for the espresso puck to reach the water temp though its incredibly hard to get an accurate read on that as I’m sure you’re aware. The starting point and ramp time of a puck is something I’m quite fascinated with and think we have a lot to learn about. We’ve been banging on about 0.1c accuracy in machines but ignoring a potential 60c jump in start temps the whole time.
    Looking forward to reading more of your thoughts on here.

    • Hi Colin
      Thanks for the comment. You are, of course, correct, that espresso grounds can be much warmer (unless pregrinding well ahead of time).
      Of course, filter grounds will be warmer than 25c, as well, though they may not be as warm as espresso grounds, in part because the finer grinding for espresso will generate more heat.

      I wanted to offer an very simple example of how and why espresso extraction temperatures would be lower than filter slurry temps. I knew someone would call me out on how oversimplified it was. ;(

      I don’t know if the atmosphere inside a pf basket is “a lot hotter” than inside a batch brewer’s basket during brewing. And certainly how the basket or pf is handled before loading and brewing may affect their surface temperatures, so that’s a bit of an x factor.

      About 15 years ago I pulled 100s of shots with a bean-probe thermocouple drilled through the bottom of a basket and mounted at the bottom of the espresso pucks. At first I thought I’d made a mistake, as early extraction temperatures would begin in the 150-155f (65-68c) range (if I remember correctly) and it took half of the elapsed shot time for the temperature to breach 185f (85c). At that point, probably 80%+ of the extraction had occurred.

      My oversimplified example aside, I think we’re on the same page. I’ve always been frustrated with baristas’ obsession with machines’ temperature consistency (and their under-appreciation of preinfusion), given the massive range of extraction temperatures during a shot. As well, people often talk about adjusting temperatures based on roast level, but no one seems to ever about adjusting temperature based on brewing ratio (use more water:grounds and the average extraction temperature goes up quite a bit). Preinfusion and adjusting temperature based on brewing ratio are much more important than having a machine with precise temperature control and no preinfusion. (Obviously this implies that I think certain popular machines are vastly overrated.)

      • Hi Scott, thanks a lot for all your excellent posts
        For my espresso shots i use a declining flow preinfusion. I start with a high flow which kind of compresses the puck then i gradually decrease the flow to almost zero. It is important not to stay close to a zero flow too long as it destroys the puck flow resistance.
        I can’t measure the puck temperature but i guess this brings up the puck temp to a stable point to continue extraction with a constant temp. I like these kind of shots very much.

  11. Hey Scott,

    From a guy who has been brewing coffees for 11 years and only just getting in to roasting coffees this was very eye opening.

    Thank you for sharing 🙂

  12. I think that a coffee roasted light with no roasty aromas, when you brew it as filter coffee, you have a ratio 1-17 and as Espresso, 1-2.
    So, the acidity in the Espresso is like 8 times stronger and most of the people wich are used in dark roasted cofees with roasty aromas and no acidity, don’t like such espressos.
    I usually brew a light roasted specialty coffee 1-2.5 to 1-3 (Lungo) for a lower acidity, but still the majority of the people don’t like it, even if its well developed , and well extracted.
    Its a big topic…
    I didn’t know this about the temperature, so Thank you Scott Rao.

  13. Hello Scott.

    Always useful information. Thank you!

    What we are trying to do in the coffee shop I work for is pulling longer shots, lungo style (20 grs. in / 50-60 grs. out). We loose in body/mouthfeel but the extraction increases and also the temperature, since more hot water is passing through the coffee puck.

    We got nice results even using lighter roasts. But Panos is right, most people still think lungos are just watery and wrong pulled espressos, even though they can be balanced.

    Thank you very much,

    Julian

  14. How about rosting a different profile for either espresso or filter?
    ending with the same end temperature and roast degree and look

    I have done so(hobby basis), roasting out more accity from the espresso roast
    it will be booring/flat as filter
    the filter as espresso ,will be like grapefruit without suggar ;o)
    and a Middle American roasted so it tastes dry and bitter like baker cacao both as espresso or filter
    but is wonderfull in milk

  15. To each there own. That’s what’s so great about coffee. But from my experience I slightly disagree. For drip I like to roast the bean so it brings out the sweetness, has nice body and still makes the origin characteristics​ shine. For espesso I’m happy with same but if it’s a milk based drink I like to go even slightly lighter​ as long as it’s a well developed light roast. Since sweetness and acidity go hand and hand i find it cuts through the milk really nicely and makes some of the nicest sweetest milk based drinks. I’ve done lots of blind taste tests with people and they always pick the lighter one and allot of times even ask if I’ve added sugar.

Leave a Reply

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