My Second Week with the MoJoToGo

Posted on May 26, 2010 by

After my first week with the MoJoToGo, and a few minor setbacks, I’ve learned a few things.

1) Never change more than one variable at a time.

Yeah, I remember this from high school chemistry too. But it’s really really tempting to jump ahead of yourself. DON’T DO IT. The extraction yield and TDS% is extremely sensitive to variations in your technique. No matter how subtle a change you think you’re making, MoJoToGo will notice it. If you make more than one change at a time you’ll eventually have to start all over again from the beginning. Which sucks.

2) Until you get a basic grasp of what’s happening, stick with one brew method.

I was pretty excited when my refractometer arrived and quickly tested several different brew methods. If you don’t know what you’re doing, jumping around between brew methods is a good way to confuse yourself. For the last week I’ve stuck exclusively to the Clever Dripper and increased the quality of my brews dramatically.

3) Grind is more important than I thought.

Not just in the whole “exposing more surface area for even extraction” kind of way. But also in the “this coffee requires a different grind than that coffee” kind of way. You know, like Espresso 101. I finished the week with Square Mile’s Capão Chapada Diamantina pretty well dialed in, but when I switched it for Stumptown’s Montes De Oro my results were so different I thought something had gone horribly, horribly wrong. After a few emails to some much smarter people, I adjusted my grind finer than I have ever gone for drip before. Like, crazy fine. And it worked.

4) I should have gotten the ExtractMojo two years ago.

  • Chris Capell

    Hey Mike — hope you're not getting tired of all my comments. :-) I do love that you're documenting and sharing this process.

    Regarding point 3, I do think that you have to change grinds when moving between coffees, but my experience leads me to believe it has less to do with the coffee intrinsically, and more to do with the degassing, ie., coffee that has degassed more extracts faster than coffee that has degassed less, and vice versa. And seeing as different coffees are usually roasted on different days, some have been in nitrogen-flushed bags, some not, bags have been opened at different dates, etc., you therefore have to adjust grind when moving between them. But if you're able, try this experiment — take two new bags of two different coffees from the same roaster, roasted on the same day, open both bags at once, and brew both with the same grind (and other brew parameters, obviously). I think you'll find they extract to very similar percentages.

  • http://shotzombies.com Mike White

    Good idea Chris, I forgot about the effect of degassing when I posted a related question on Coffeed:

    http://www.coffeed.com/viewtopic.php?p=30552#p3…

  • Chris Capell

    I just read the coffeed thread — yeah, it's definitely the effects of degassing that you're noticing. With fresher coffee, the gas is coming out faster/more powerfully, and it ends up pushing the water away more throughout the brew, resulting in less extraction of coffee solubles. So you need to grind finer with fresher coffee, or brew longer. (When I first got into espresso, I read somewhere that you should grind finer as it ages, 'to get more of the good stuff out as the coffee stales.' I now know that in fact I should grind coarser as it ages, because it extracts faster, and maybe updose a little if I find the espresso weak or lacking in body due to the reduced surface area exposed.) Thus, what seems 'counter-intuitive' makes sense once you understand the underlying process — with the caveat of course that what we 'understand' in coffee today can be overturned by new information tomorrow, because it's still really early days for all of us in our knowledge. :-)

    BTW, another side-effect of degassing is that grinds from fresher coffee have increased Brownian motion; they bounce around and push away from each other more intensely, and thus tend to stick more easily to the sides of cone-shaped brewers like the V60 or Clever during drawdown. Fresher coffee therefore needs to be agitated more vigourously in order to counter this and still attain the right final coffee bed shape as per Rao, 'Everything but Espresso.' Helpfully, this helps to counteract the slower rate of extraction a little. :-) In short, stir more with fresher coffee, less with older, more degassed coffee.

    And a second BTW — isn't it great how using Mojo immediately makes these kind of things apparent? You could instantly see that fresher coffee extracted slower — without this tool, how long might it have taken to figure that out? So, where do I get my 'Vince Fedele for President' shirt?

  • Chris Capell

    I just read the coffeed thread — yeah, it's definitely the effects of degassing that you're noticing. With fresher coffee, the gas is coming out faster/more powerfully, and it ends up pushing the water away more throughout the brew, resulting in less extraction of coffee solubles. So you need to grind finer with fresher coffee, or brew longer. (When I first got into espresso, I read somewhere that you should grind finer as it ages, 'to get more of the good stuff out as the coffee stales.' I now know that in fact I should grind coarser as it ages, because it extracts faster, and maybe updose a little if I find the espresso weak or lacking in body due to the reduced surface area exposed.) Thus, what seems 'counter-intuitive' makes sense once you understand the underlying process — with the caveat of course that what we 'understand' in coffee today can be overturned by new information tomorrow, because it's still really early days for all of us in our knowledge. :-)

    BTW, another side-effect of degassing is that grinds from fresher coffee have increased Brownian motion; they bounce around and push away from each other more intensely, and thus tend to stick more easily to the sides of cone-shaped brewers like the V60 or Clever during drawdown. Fresher coffee therefore needs to be agitated more vigourously in order to counter this and still attain the right final coffee bed shape as per Rao, 'Everything but Espresso.' Helpfully, this helps to counteract the slower rate of extraction a little. :-) In short, stir more with fresher coffee, less with older, more degassed coffee.

    And a second BTW — isn't it great how using Mojo immediately makes these kind of things apparent? You could instantly see that fresher coffee extracted slower — without this tool, how long might it have taken to figure that out? So, where do I get my 'Vince Fedele for President' shirt?

  • Scott

    Hi again Mike,
    I've been wondering about the differences between TDS type and native type… The refractometer i had (broke) could do both – how do you choose which to use and why.
    What you have you learned about this?
    thanks for sharing, love it.
    sL

  • http://shotzombies.com Mike White

    I have not used it in TDS mode. As I understand it Native mode using high quality refractometers (such as VST's) is more accurate, enabling MoJoToGo to calculate results with more data (like temperature). But native mode is required to read espresso and different sugars. Originally I think they were entirely separate refractometers that MoJo was selling, and now they've been combined into a single unit with both modes.

  • http://shotzombies.com Mike White

    I've used a couple of different grinders, and have been starting with 15g/250g with a 4 minute dwell. I now suspect that the batch of Montes De Oro is slightly underdeveloped, but will have to test some more to confirm this.

  • http://shotzombies.com Mike White

    “I would guess then similarly to Nick, that it must be some other variable in play.”

    Like an underdeveloped roast? That's what I'm leaning towards now…

  • ccapell

    Do underdeveloped roasts tend to extract slower? I know very little about roasting yet, but I would have thought that roast degree mostly related to what the compounds that do get extracted are/taste like, rather than the rate of extraction. But I guess it's entirely possible that if the coffee doesn't get roasted to a certain degree, the compounds don't get created/modified into an easily extractable form. Would love to learn more about this…

    If you do get a chance to try another pair of coffees of different ages to at least see if they conform more to the 'older extracts faster' paradigm, let us know!

  • Anonymous

    Do underdeveloped roasts tend to extract slower? I know very little about roasting yet, but I would have thought that roast degree mostly related to what the compounds that do get extracted are/taste like, rather than the rate of extraction. But I guess it’s entirely possible that if the coffee doesn’t get roasted to a certain degree, the compounds don’t get created/modified into an easily extractable form. Would love to learn more about this…nnIf you do get a chance to try another pair of coffees of different ages to at least see if they conform more to the ‘older extracts faster’ paradigm, let us know!

  • SewiousDeliwium

    I’ve checked the VST website, but was confused by the number of kits on offer! What do I need to get started? I’d hate to think I’m missing a way of getting the best from my beans… I have an iPhone with the MojoToGo coffee app. Many thanks!

  • http://shotzombies.com Mike White

    All you need is the VST Coffee Refractometer, the first refractometer listed here: http://vstapps.com/store/. It will work with both coffee and espresso.

  • http://www.koffietmolentje.be Laurent

    Great coffee video! Thanks a lot!