Now that I weigh every shot both the grinds and the shot, where would the Extract Mojo fit in? What I mean is that I am now controlling temps with PID, controlling the dose, controlling the extraction by getting a xxgm dose in xx seconds, what else can you adjust if the Extract Mojo numbers aren't equal to another user?

mitch236 wrote:Now that I weigh every shot both the grinds and the shot, where would the Extract Mojo fit in?

It would mean you have successfully converted the pleasant ritual of preparing a little cup of coffee into a full-blown obsessive-compulsive disorder. In other words, you will have earned a place in the Home-barista Hall of Fame!

I think you've hit the nail on the head there, Jim. The EM allows a number of different baristas (and bars in a chain) to meet a "house standard" consistently without constant supervision. This makes it valuable in a commercial environment but much less so at home where you mainly brew to please yourself.

another_jim wrote:I think this is definitely true when calibrating brewers, espresso gear and procedures in a cafe. I do not believe it is true for the way I make coffee. I can mostly get to the taste balance I want after one adjustment to weight and grind, two at most, either when brewing or making espresso. Therefore, doing an extract mojo measure takes more time, effort and expense.

I think if you dial in rarely, doing it very precisely, and stick to that dial in for as long as you use the same coffee; your procedures are more analogous to a cafe's; and the extract-mojo might be beneficial. If you automatically adjust grind and dose of your next shot based on the taste of the previous one, and do it well, your procedures are more analogous to what I do; and the extract-mojo doesn't fit into the flow.

I have no clear idea where along this spectrum most HBers fall, or at what point of sticking to permanent dose, grind and extraction settings taking refractometer readings becomes a plus.

Jim, I agree that your way of making coffee is at one end of the spectrum. After years and years of cupping coffees and roasting, making and tasting espresso, you have what they call automaticity. You don't have to sound out the letters to read a word; you don't have to think about specifically what you're doing when you drive a car. You can taste espresso and know exactly what to do to move the flavor profile where you want it to go.

But I think the other end of the spectrum isn't necessarily the home barisata who dials in carefully and sticks with the settings. I think the other end of the spectrum might be post-newbies, like me, who after a couple of years are beginning to understand the interplay between origin, blend, roast, dose, grind and extraction weight. We're making progress on this front, but we haven't achieved automaticity.

My question is whether the ExtractMojo would provide one more piece of information, the coffee concentration, that would inform my espresso making and lead to automaticity. Knowing the extraction weight has been much more useful than volume for achieving consistency, but I find it less useful as a correlation with taste. I think that's because the extraction weight is made up of two variables, the weight of the water and the weight of the coffee solubles. I don't know the ratio, so I don't know how much of the weight I'm seeing is due to coffee and how much is due to water. Nor do I know how the ratio affects taste.

Knowing this, of course, will only be useful if the concentration correlates with taste. The concentration has to consistently fall into some magic range (either mine or the one accepted by coffee professionals like Scott Rao of 19%-20%) whenever I hit the taste I'm looking for. Then it has to be possible to correlate that concentration with changes in the dose, grind and/or temperature.

My hope would be that I would get a better handle on which variables to change to move the flavor profile in the direction I'm seeking. Of course, there's also the question of whether the magic concentration range is constant or varies with different coffees. The literature, and proponents of the device would say the former; if it's the latter then the information may be of limited practical use.

But if, as you said in an earlier post, the concentration doesn't correlate with taste, then I don't see how the instrument would be of much use to anyone.

To me, instrumental numerical values will be helpful only if it gives me information so I can adjust my technique to improve taste and consistency. There are likely numerous ways to achieve this. I think weighing the espresso with portable scales that were discussed earlier is likely sufficient. Similarly, I have been weighing drip and Abid for a while.

My thoughts and questioning about EM were not well received previously at CG, and hopefully my posting again this time will not stir another similar discussion.

After one goes through the procedure of EM, at least at home, it appears it will be difficult to correlate the reading with taste. It will give a very detailed numerical information, though. Can my tongue/nose detect the difference down to 0.1% TDS? Probably not.

It is akin to using a laboratory analytical balance to weigh the coffee beans, or use an Agtron spectrophotometer in home roasting, or a $30 dollar vs $100 tamper. There are simpler and more efficient bang for the buck methods. But if you have the fund, why not.

Disclosure: I have never used an ExtractMojo, but I have discussed its use with Andy S. One of these days I might buy one, but I have no plans to do so at present.

This device has provided some independent support for the idea of trying to control for the extraction yield of dissolved solids from an espresso dose in a PF, and to keep it in a range that extractions can be consistent. I believe but can't prove that you can accomplish much the same thing by weighing the coffee you put into the PF, then weighing the shot in real time as it is produced, so long as the shot duration is kept within a certain range.

I state this nebulously on purpose, because the idea I have is that all that really matters is the taste of what you are producing, not an absolute number that is produced on some sort of measuring device. In this way, the process is not dissimilar from calibrating shot temperatures by taste rather than by thermometry, although you might use thermometry later in order to remain consistent (such as one would use a scale to keep extractions consistent).

For myself, what I have learned from weighing shot doses and then weighing shot extraction weights, is that although I used to think I preferred ultra concentrated ultra ristretto-ish shots, I have learned, courtesy of Andy S, that in fact my shots taste better if they weigh considerably more than I used to think they should weigh. So now my shots are larger in volume and in weight, and they taste better to me.

Perhaps this could have been done empirically without the use of an ExtractMojo, however its existence appears to have aided some in defining what exactly was the goal of what they were trying to study. Regardless, I doubt that this device needs to be in the toolkit of home baristas, but a cheap 0.1g scale probably should be.

ken

Ken Fox wrote:Perhaps this could have been done empirically without the use of an ExtractMojo, however its existence appears to have aided some in defining what exactly was the goal of what they were trying to study. Regardless, I doubt that this device needs to be in the toolkit of home baristas, but a cheap 0.1g scale probably should be.

Indeed. It's easy to justify $7 for a 0.1g scale but it's a whole other matter to justify $600 for an ExtractMojo with all the required accessories, even for people who have spent a lot of money on espresso gear (I don't see anyone around here who fits that description, do you? )

chang00 wrote:To me, instrumental numerical values will be helpful only if it gives me information so I can adjust my technique to improve taste and consistency.

Right! What he said.

chang00 wrote:After one goes through the procedure of EM, at least at home, it appears it will be difficult to correlate the reading with taste. It will give a very detailed numerical information, though. Can my tongue/nose detect the difference down to 0.1% TDS? Probably not.

That's what I keep wondering. Can I taste the difference revealed by the ExtractMojo, and can I use it to tailor my shots?

I'm speculating, but I doubt it. I think the reason has to be that there's yet another layer of variables underneath solubles concentration: the composition of the solubles. As Jim has pointed out in his articles and posts on extraction, different solubles are released at different times and at different temperatures during the extraction process. The exact mix varies with the coffee species, origin, processing technique, roast level/technique, blending, etc. (and a good thing it does -- our espresso hobby would be dull indeed if this wasn't so.)

The proportions of the different solubles present in the extraction determine taste. But the ExtractMojo doesn't tell you anything about that. At best, it would seem, it's a measure of intensity -- the concentration of all the different solubles taken together. Rao claims that concentrations over 21% tend to be bitter, and I suppose that's useful information, but it's also easy to taste and correct. Intensity and balance are important, but there's more to optimizing taste than that.

At present, it seems the tongue is the only affordable instrument capable of revealing anything important about the composition of the solubles/water in the cup. Unfortunately, tongues are not scientific instruments and we each have our own set of buds to correlate with the complex flavors in the cup. Seems to me this is one reason newbies can't learn how to prep great espresso just from reading a few posts from the experts. It takes time.

I guess after all this discussion I've come full circle. Jim is right that ExtractMojo probably makes sense as a consistency tool for cafes, but not as a tool for home-baristas. I also agree with Jim that what one learns about espresso with inconsistent gear is mostly wasted. It was only after getting consistent gear, especially the grinder, that I've been able to engineer taste to any appreciable degree. But I still think he's better able to know what tastes to expect from a given coffee because he's been a student of the field for a long time.

My point is this: I make good espresso now (if you ask my wife), but I see a long road ahead to get really good at it. Evidently, ExtractMojo won't provide a shortcut.

I've owned a VST coffee refractometer for a couple of weeks. I had considered the purchase for almost a year, but didn't think I could justify the cost. I have only used it for regular brewed coffee so far, and don't intend to get into espresso with it right away, thought I did purchase some of the required syringe filters.

I have had a number of interesting coffee brewing sessions so far. I do not consider myself a particularly great coffee cupper. I found it quite enlightening to see what sort of difference adjustments to grind and brewing technique make to the extraction characteristics of the coffee. I now have a much better idea of the sort of adjustment you need to make to have a meaningful impact on the taste. Being able to correlate my own taste with a measured value is very useful. When I am experimenting with the EM, I always taste the coffee first to see where I think they fall, and I am getting better at predicting the result.

Yesterday I was especially surprised by how easy it is to underextract coffee with a French press, and how much it depends on brewing method with such a coarse grind. I am now making noticeably better press pot coffee after adjusting some parameters. It was kind of neat later reading James Hoffman's thoughts on the same subject and how it has changed the way he brews coffee for the better.

chang00 wrote:My thoughts and questioning about EM were not well received previously at CG, and hopefully my posting again this time will not stir another similar discussion.

Your thoughts and questioning were not well-received on CG because you weren't just questioning the value of TDS readings, but demanding peer-reviewed journal publications from Andy and Vince proving EM can actually produce accurate TDS results for espresso. It doesn't seem like Vince's reply satisfied you.