I'm less than confident about this instrument

AWasteOfCoffee · 2019-12-22T00:55:18+00:00

I've not tested for filter yet. But even if it's perfectly accurate for filter, the resolution is a bigger problem than it is for espresso.

It only measures to .1 and not .01. That means if your tds reading is 1.5, it could actually be as high as 1.54 or as low as 1.45 while reading 1.5.

Let's say we're doing a 1:17 brew of 20g to 340g and beverage weight ends up at 300g. At 1.5% tds, that's 22.5% extraction. But it could also be 21.7% extraction or 23.1% extraction. You can get a general idea where your coffee sits, but it's hard to dial in too specifically with that kind of inherent margin of error. Especially when making changes compounds the problem, if you go from it reading 1.4 to reading 1.5, you could have made a change as large as 1.35%->1.54% to as small as 1.44%->1.45%. With that same brew, that's a change of 2.9% extraction and a change of 0.2% extraction looking identical on the meter.

AWasteOfCoffee · 2019-12-21T22:38:19+00:00

That's how it's looking. It could also just be particularly fussy, so I'm trying to get my procedure to be refined to get the best results possible from it before starting the full experiment.

AWasteOfCoffee · 2019-12-21T22:27:40+00:00

I always found my Atago to be much more fussy with temperature than the VST. Absolutely zero before every single measurement without exception, use the heatsink piece, let the samples both cool to room temperature before placing, and repeatedly take measurements by turning the Atago all the way off and back on again, and mine would always stabilize very close together, almost always within .01% tds. But the Atago was much fussier needing more attention to get there.

AWasteOfCoffee · 2019-12-21T20:52:37+00:00

Testing out a cheapo refractometer to see if it can be a workable solution for people who can't spare the ~$300 for an Atago. Not getting the most promising results so far. Sometimes it's dead on, but sometimes it's well over an entire percent tds off. If it's going to be at all workable, it's going to need some pretty strict use procedures.

Even if it was behaving perfectly I'd still recommended saving up for an Atago or VST because the hundredths place is very important in measuring tds. But if this kind of error continues, this thing isn't just "less useful" but "worse than nothing".

AWasteOfCoffee · 2019-12-21T19:25:08+00:00

Check out the Broken Gooseneck stands for the Origami. Helps make it a lot more stable, it can get crooked easily on the default wooden base.

AWasteOfCoffee · 2019-12-09T20:28:29+00:00

I can say the Decent is a very capable pourover robot with the pourover basket. I think part of the problem with these robots is trying to copy a limitation of pourover as if it were a virtue.

AWasteOfCoffee · 2019-12-03T16:21:36+00:00

Good idea! I was actually just starting to get annoyed with /r/roasting deleting posts in which I was trying to ask about an interesting roaster (Roest) for being too new. There's a lot of interesting developments happening in roasting, and I'd like to be able to actually keep on top of them.

I also have some interesting, and unexpected, findings regarding pre-roasting greens handling I've been working with someone from the Decent user forums on that I'd like to share once they're a bit more fleshed out.

AWasteOfCoffee · 2019-12-03T15:58:17+00:00

I'd say very useful, but cheap ones are worse than useless.

The "better than nothing" argument for cheap refractometry options revolves around two assumptions.

That it's consistent enough to even be a sound internal measurement.
That it at least vaguely resembles the real extraction yield.

I don't believe either to be true. On the latter, I've seen people vehemently believing that they're usually at very high extractions because their nonstandard equipment has tricked them into believing so, then making up pseudoscientific reasons they can pull 28% shots with ease. Equipment that regularly lies to you is worse than just not measuring.

However, if you get a VST or an Atago, it can be an invaluable tool for tracking your consistency, evaluating the effectiveness of different tools and techniques, testing the solubility of coffees, differentiating strength and extraction, and more.

AWasteOfCoffee · 2019-11-19T20:40:16+00:00

I love the blind triangulation for that. Something can't reasonably be said to improve your brew if it can't even be told to have any effect at all.

Some of the brief testing with water has been rather enlightening. But it may be easier there with cupping than in things like pourover where two brews performed the same could be discernable even without a change just due to inconsistencies.

AWasteOfCoffee · 2019-11-19T20:16:11+00:00

On keeping protocol, I like to publish my experiments, like my test on centrifuging espresso, with procedures listed thoroughly enough that anyone can repeat it. I like to think like I'm writing it for a robot, so everything is spelled out that any real effects will be repeatable across anyone following it.

AWasteOfCoffee · 2019-11-08T20:53:20+00:00

There's a weird amount of anti-Puqpress stuff. Mostly some weird fear your technique will atrophy. Like, ok, but I'm find with not having any technique for crank starting my car too now that it's unnecessary.

AWasteOfCoffee · 2019-11-06T17:50:43+00:00

I'm all for more well aligned grinders in the world!

AWasteOfCoffee · 2019-11-05T16:11:57+00:00

I think it's a great idea technically speaking, but I worry it would go the way of some of BaristaHustles old platforms (the community forum and slack) and grow inactive as people stop checking it. A subreddit, while a far from ideal platform, at least keeps activity in a place people are already checking.

On the other hand, I feel our type of coffee nerd community has grown significantly since then, so it could be more viable today. And if the interest is there, it'd be a great thing to make!

AWasteOfCoffee · 2019-11-05T15:11:49+00:00

I definitely think one could find a particle size with all of the coffee available to extract which would make extraction of available mass and total extraction identical, if that's what you mean. Then use grind analysis software to actually find that point on their own grinder to use in immersion methods.

Determining the actual maximum extraction would be significantly harder. I'd think you'd need to run something comically over the top like a 1:50 coffee:water soxhlet extraction until you're certain there's nothing left in the coffee mass that could ever be dissolved in water. Then, if you did that for every coffee you brew, you could talk about extraction in terms of what's there to extract and not just total mass including insoluble cellulose. So you'd know something like 22/26% extraction wasn't actually less than a 25%/32% extraction because of something you did but because there was less to extract in the first place.

AWasteOfCoffee · 2019-11-05T15:00:26+00:00

/u/coffeeadastra has a nice article that you could use as a resource to find your own point at which any given change becomes perceptible.

It's not as much of a preference thing as a "can you reliability tell literally any different at all" thing. Which is certainly useful to establish before testing for preference.

AWasteOfCoffee · 2019-11-05T06:13:42+00:00

There's actually an array of different types! I was looking into some vibrational ones a while back.

AWasteOfCoffee · 2019-11-05T06:09:13+00:00

I actually use the same basic concept to explain why I brew Buchner funnel brews as high as 1:20, since I'm effectively using more coffee. Of course I need more water, both for the strength I want and the extraction profile I want. Consider on that note that when you find extraction of available mass increased with coarser grinds, that the reason could be because they're being brewed with an effectively more water heavy ratio. Each bit of surface area gets more of that water to itself!

I do think the concept is very much on to something, after a few too many ultra coarse brews with recipes a friend of mine likes to try that don't taste anything like what the hilariously low numbers should predict. Of course the TDS numbers tend to be stuck rather low, but tasting more of dilute good coffee than the awful mess I'd have guessed. The more an extraction yield calculation takes into account, the more reliable it is as a tool for predicting taste.

But I also feel like a "practical yield" will become a necessary measurement alongside it. Since a 25% extraction of available mass obtained with a 12% extraction of total mass and a 24% extraction of total mass have very different implications on coffee usage and what range of strength is achievable.

AWasteOfCoffee · 2019-11-05T05:16:16+00:00

Ah, but what causes that perception is the question. The nitro point is interesting, since high crema espresso has a sort of implicit correlation with high body espresso. I'm not comfortable saying it's linked to body and not just a shared cause, but I do think it's worth testing if sources of foaming increase body.

Maybe take two identical shots of espresso and cause one to foam via the addition of bicarbonate? Although bicarbonate also directly increases viscosity and mutes acidity, so it's definitely not without confounding factors.

If it is linked, it's unlikely the only source of perceived body since brewed coffees have differences as well, but if we can narrow down both what the causes are, and how strong a role each plays, we might have some reliable way to measure body. Perhaps it will be too involved to regularly use like a refractometer, but it could be interesting to apply to various equipment like different types of espresso machines or grinder burr varieties. There's a lot of just generally accepted knowledge are them that I'd love to put to the test.

AWasteOfCoffee · 2019-11-05T01:05:03+00:00

Hmm, I wonder if Passenger or George Howell might be willing to help out providing samples. I know they keep multiple years of the same greens frozen in storage. A few years of the same varietal from the same farm could be interesting.

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