Breaking a Bad Habit

Just like you, I know lots of people who spend time thinking about how they can help the contemporary coffee scene move forward. And being a tech head, the ideas I have for this tend to be techie ones. Although it isn’t the first time, I want to advance (again) a technique that I believe will eventually help us all make better espresso.

It’s so simple, it sounds trivial or even silly:

When you talk to others about how you make your espresso, specify the “volume” of your shot in units of mass (grams) rather than units of volume (ounces or milliliters).

Of course you are asking, what difference will THAT make?

Well, most people would agree that the last ten years have seen tremendous progress in espresso quality. The shots pulled at recent barista competitions are far better than those pulled ten years ago. This is due to hard work by farmers, greens buyers, roasters, baristas, and machine designers, but it’s also due to the ease with which those same people can share experiences with their colleagues. Exchanging tips and techniques via web, email, video, etc. has revolutionized the way we teach each other to make espresso.

Every barista knows that a crucial part of how we make an espresso is the shot “volume”: how “ristretto” or how “lungo” it is. And reporting how many GRAMS of espresso we extract is FAR more useful than reporting in ounces or milliliters.

WHY?

  1. Espresso volume is a moving target. Day by day, as beans age, the volume of crema they produce decreases. This can make a 20% difference in measured volume.
  2. Spouted portafilters collapse crema as espresso runs through them. A spouted shot will measure 10-15% lower in volume than the identical shot through a bottomless portafilter.
  3. The calibrated shot glasses that many folks use to measure volume are not precision measuring devices. Many of them are off by 5% or more.
  4. As crema dissipates, espresso volume decreases. If you hesitate even a few seconds before measuring, the volume has changed.
  5. A shot that runs a few seconds longer than usual will measure lower in volume simply because the crema bubbles are bursting in the cup as the extraction proceeds.

Add these factors up randomly and one person’s “1.5 ounce shot” can be vastly different from someone else’s.

In contrast, espresso shots measured in grams weigh the same whether there is lots of crema or little; whether pulled through bottomless or spouted; whether weighed immediately or a minute later. And even a cheap $20 gram scale is more accurate at measuring weight than our shot glasses are at measuring volume.

Aside from the pure accuracy of using grams rather than ounces/millimeters for espresso volume, there are other benefits:

  1. You begin to think of “ristretto,” “normale” and “lungo” shots as ratios between grams of dry coffee dosed and grams of beverage extracted. The confusion that results from the haphazard use of these terms suddenly vanishes.
  2. Measuring the amount of espresso beverage in grams is an essential first step in calculating extraction yields with ExtractMojo or MojoToGo. I am confident that this technology will have a huge impact on our industry.

Unfortunately, our bad habit of measuring espresso in ounces/milliliters seems to be a very hard one to break. So far it is too radical a concept for most coffee companies: Intelligentsia, Counter Culture, 49th Parallel and Stumptown post instructions for using their espresso coffees, but sadly, they measure extracted volume in ounces.

Make no mistake, I have big respect for these great companies, but since they trust us enough to specify the coffee dose in grams, why do they assume we’re too lazy to measure the amount of espresso in grams? These companies could help move things along by taking a tip from the prodigious and open-minded James Hoffmann: as a compromise, try using ounces or milliliters AND grams for the amount of espresso extracted. Here is a recent Square Mile brew recipe for one of their espressos:

Dose: 20-21g
Brew Temperature: 200°F/93.5°C
Brew Time: 25-28s
Total Volume: approx. 50ml
Brew Ratio: 60% – approx 30-35g of liquid

James, you are awesome!

-AndyS

24 Responses to Breaking a Bad Habit

  1. Bryan says:

    This is a really good point and I’m having quite a ::facepalm/duh:: moment right now.

    Thanks.
    -bry

  2. Mark Prince says:

    Add at least one more company to your list Andy – Vince Piccolo’s been using gram scales for his shot volumes for at least a year or longer, and it is part of his structure on how they recommend Epic to be pulled.

    It took me some time to wrap my head around it all, mainly cuz Vince pulls at nearly a 1:1 ratio (19.5g coffee, 19.5g espresso brewed), and it was always very tight for me being fairly anti ristretto. I got hung up on Vince’s “do a 1:1 ratio” when thinking through the weights.

    I’ve been using several gram scales in the Lab since last fall for all shot calibrations and dial ins – a big 5kg scale (.1 gram accuracy) for weighing PF and coffee, and some nice 500g 0.01g scales for measuring the shots. It has been a big boon for consistency and testing. Tied in with the FrankenLinea and GS3/MP, shots is TIGHT where control and repeatability are crucial.

  3. Wilson Hines says:

    I’ve been measuring out every single shot in grams since the SERBC this year. Wow, it makes a serious difference. I should say, a “measurable difference.”

  4. Lisa says:

    Isn’t oz a weight unit as well? One can calibrate to decimal points in any weight unit right? Why does it have to be grams? Don’t get me wrong, I like metric. Just trying to understand if there’s any additional subtle differences.

  5. Nicklas Haraldsson says:

    This is an important point. I have recently been looking in to baking bread and the trend there seems to be more and more going towards weight measuring rather than volume. The same thing goes for chocolate, when looking at recipes are quite often based on wight since a small error can change the result quite much when it comes to chocolate.
    So others have adapted weight instead of volume measuring to rule out error, so the coffee community should gain from a change towards measuring more by weight!

  6. John Piquet says:

    It’s great that this has FINALLY trickled out to the “professional” community after nearly three and a half years.

    I’ve been pulling shots based on ratio for over a month now after reading Andy’s original post on Home-Barista. I have dabbled with it from time to time before, but never sat down and read the actual simplicity of what Andy was saying.

    With “dose by weight” and “X oz. of water” being so important in both espresso AND coffee preparation, it seems odd that the community as a whole hasn’t thought about the importance of “weight” in the final drink. The obviousness has been staring all of us in the face for a long time. Sometimes, we’re all a little slow. Thanks Andy, your coffeetechgeekiosity is appreciated.

  7. andys says:

    Bryan, Nicklas and John: thank you for taking the time to read and comment.

    Mark: I spoke with Vince after reading your comment, and he confirmed what you say. BUT, a while back he took the ‘beverage by weight’ specs off his website because people were getting confused. After talking with him, I think he’s going to use both volume and mass measurements on the site.

    Wilson: Glad this works for you. Personally, I don’t weigh EVERY shot, but I find it’s useful to do so regularly (as a reality check) and necessary when doing experimental stuff.

    Lisa: Yes, the ounce is a unit of weight. But there’s the avoirdupois ounce, the troy ounce, the Maria Theresa ounce, the Dutch Metric ounce…. Then there’s the volumetric ounce and the ounce-force. What a mess. I like good old boring grams! Besides, since everyone uses grams to weigh their espresso dose, it makes the formula for Espresso Brewing Ratio simple:
    dose(grams) / espresso(grams).

  8. Rick Nakama says:

    I like this information! Very good!

  9. Thanks for the shoutout but a bigger thanks for putting me onto this three and a bit years ago.

    Weighing shots has been incredibly useful in a number of situations:

    - Trying to pull shots of extremely fresh coffee
    - Diagnosing problems remotely/via email
    - Trying to be even vaguely consistent behind a coffee machine
    - Understanding flow rates better
    - Using the Mojo kit.

    What frustrates me is how awkward the process is. Many reasonably accurate scales aren’t built to be around espresso machine drip trays. More than this they have an irritating lag between realtime weight and displayed weight. This can be up to 5g.
    This will truly become useful when you have quick, realtime shot weight feedback as you are brewing.

    It does make you wonder though – if volumetric/brew water weight accuracy could be improved through flowmeters, would many places be better off using them?

  10. CBB says:

    The only thing I don’t like about this is that it wastes a lot of coffee.

  11. andys says:

    James: I’ve been using a $21 miniature scale that has very little lag:
    http://www.americanweigh.com/product_info.php?cPath=60&products_id=1870&osCsid=619d02ecbb19562d7c07d8c8b8ba2253
    Still, you have to kill the shot 1 – 1.5g early.
    I agree re:flowmeters, they can be quite useful for stuff like this.

    CBB: I don’t understand your comment.

  12. nickcho says:

    I’m a little confused… I thought Andy had put this extraction-ratios (by mass) thing out there years ago! Oh well, still nice to see it re-stated.

    One little beef: I don’t mean to rain on anyone’s parade, but between the extraction-ratio talk and the ExtractMojoToGo, there’s one little caveat that people need to keep in mind: these are absolutely valuable tools that are big improvements over the available alternatives, BUT they do both somewhat assume optimal conditions.

    Absolutely, measuring espresso extractions by mass is more reliable and more useful than fleeting and unreliable volume. However, uneven extractions (including channeling) will somewhat thwart the whole thing.

    I love the Mojo. However, certain brew methods render the extraction yield figure less relevant: some brewing techniques involve a quantity of coffee grounds that does not much interact in the brewing. The TDS is still valuable, and it’s still much better than not having a measurement tool at all, but it’s something to keep in mind.

  13. Tim S says:

    can i throw a question into the mix? Here goes:

    If you had a nice espresso double shot at 2ounces and you had a cup of water at 2.5ounces, wouldnt they be the same weight in grams? in other words, the ground coffee adds some mass to the water and so the volume of espresso is less than the volume of an equal mass of water. This is important if you get some mild channeling and definetly if you get a gusher.

    “Recipes” should include volume AND mass together. Most of us home baristas wont get a mojo kit, but we can get an extraction ratio of sorts by comparing volume to mass.

    admittedly, AndyS puts us on to a huge factor that most of us ignore, mass. But we cant forget about volume either. AndyS might be insuating through his critiques of volume that volume isnt important.

  14. andys says:

    Nick: Sure, I’ve been talking up the measuring-espresso-volume-by-mass thing for years. (Almost) nobody uses it, and I think that’s a shame, so I’ll keep talking about it.

  15. andys says:

    TimS: The point of my post is that an “espresso double shot at 2ounces” is a terribly imprecise measurement. Bottomless or spouted? Three day old beans or eight day old? Measured instantly or 20 seconds later?

    In any case, a given mass of espresso (with crema collapsed completely) occupies only ~2% less volume than the same mass of water. This too close for our crummy shot glasses to reliably distinguish. “Recipes” do NOT need to include volume, and home baristas WON’T get an accurate extraction measurement by comparing volume to mass.

  16. Tim S says:

    AndyS,

    That makes a lot of sense. Thanks so much for your contribution to the world of coffee. This ~2% thing makes sense to me.

    If we drop volume from the “recipe”… would you suggest mass and time as the key measurable factors in a good pull? OR mass alone as the key measurable factor?

    Thanks again!

  17. andys says:

    Nowadays, I guess a “recipe” needs to include dose, brew temp, brew time and grams espresso. Many people would also specify how many days the coffee should rest after roasting.

    In a couple years, we’ll probably be far enough along to throw in a few more items: basket depth/hole configuration, brew temperature profile, pressure profile, solubles yield.

  18. AndyS says:

    > certain brew methods render the extraction yield figure less relevant

    Nick, talk about deja vu: do you have actual experience measuring “less relevant” extraction yields with these “certain brew methods,” or is this still just speculation (as it was last year)?

  19. Cory says:

    I’ve been doing this since opening my shop just over a year ago but find it rather difficult to get the average coffee consumer to make this change in his/her conception of what an espresso is and how one is made. I’d hoped for more from such a technically minded people as the Germans… Those who do catch on, however are very grateful and it often seems to spark a sort of “aha” moment. Keep it up!

  20. andys says:

    Cory, if you have any customers at all who care enough to weigh the occasional shot that they make at home, I’d say you have a dedicated group of customers!

  21. [...] know Andy Schecter posted about this on Portafilter less than two months ago – and now I just sound like a broken, whining, complaining record. [...]

  22. [...] know Andy Schecter posted about this on Portafilter less than two months ago – and now I just sound like a broken, whining, complaining record. [...]

  23. Wayne says:

    It seems to me that volume is only an issue if you are measuring it AFTER the shot is pulled or by what the shot looks like in the cup.

    I use a volumetric dosing machine (full automatic VS Semi auto that many here seem to be using BUT not to be confused with a Super Auto which does everything for you)

    With volumetric dosing, the same volume of water is used for each shot, regardless of what it looks like in the cup. You adjust the amount of grounds in the basket to get any concentration of extraction you desire, time and time again. Problem solved

  24. andys says:

    Hi Wayne:
    I agree that automatic machines with volumetric dosing can be useful. But they do not allow baristas working on different machines to compare notes on how they are pulling shots. Automatics only can repeat shot parameters on the SAME machine.

    Enhanced communication among geographically-separated baristas is pretty much the point of my post.

Leave a Reply

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

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>