The impact of filtering on refractometer TDS and extraction yield measurements - Page 5

Beginner and pro baristas share tips and tricks.
User avatar
AssafL

Postby AssafL » Feb 16, 2019, 5:04 am

CwD wrote:... Those are an important part of espresso, but they don't make it espresso nearly as much as the high TDS does.


That is a great point. How do you know?

Nobody is preventing you from making high TDS instant coffee. Just use less water. - and stir a lot. Arguably the main difference would be the emulsified coffee butter. May be other differences as well.

In regards to the residue in the centrifuge - try upping the speed. As far as I remember Higher gravity centrifuges separate suspensions more. Maybe they can separate the fat globules?

BTW - I am pretty certain Nestle extract well. Not just because of their quality mindedness - but mainly from greed: buy for as little as possible, extract *as much as you can*, charge as much as you can per can and sell the leftover as plant food.
Scraping away (slowly) at the tyranny of biases and dogma.

CwD

Postby CwD » Feb 16, 2019, 5:20 am

AssafL wrote:That is a great point. How do you know?


Did you even read the first half of my post? You can easily test just dissolved solids, just lipids, and just sediment. The first is pretty much espresso but not quite right. The other two are very much not espresso.

AssafL wrote:In regards to the residue in the centrifuge - try upping the speed. As far as I remember Higher gravity centrifuges separate suspensions more. Maybe they can separate the fat globules?

It spins at 13,000rpm and gets everything out, confirmed by the comparison to VST. My point is that that little bit is all that is in the sample, with Turkish having many times more per sample. It also does get the fat out, which is how you can easily test the taste of just lipids, like I said in the first half of my post.


AssafL wrote:BTW - I am pretty certain Nestle extract well. Not just because of their quality mindedness - but mainly from greed: buy for as little as possible, extract *as much as you can*, charge as much as you can per can and sell the leftover as plant food.


Well isn't just high, it also needs to be done evenly. Something they probably don't care about much at all. And they probably don't push it as high as possible without reaching the bad stuff, it's easier to just bring that along too. And even perfect extraction of terrible coffee is still terrible.

User avatar
AssafL

Postby AssafL » Feb 16, 2019, 5:33 am

I did read the first part of your post. It rested on TDS being the bulk in your experience (my guess as % of the layers in the centrifuge, butter, then liquid TDS then particles at the bottom).

That is like saying chicken soups is water. If you were to centrifuge chicken soup that is what the majority would be. But the chicken fat and chicken solids make it into soup.

Or salt. A tiny 0.5% makes ice cream flavorful. 1% makes stews not be bland. 1.5-2% makes potato chips salty. Much more than a mere analysis would suggest.
Scraping away (slowly) at the tyranny of biases and dogma.

CwD

Postby CwD » replying to AssafL » Feb 16, 2019, 6:04 am

That is in no way what the first part of my post was about, that was a small sidenote in the last part of my post. My first part is about separating the components to taste just water with sediment (which tastes like gritty water, mostly), just coffee oils (which taste just horrible when isolated), and just dissolved solids with no oils or sediment. The sediment and oils are very clearly not espresso by themselves by taste (not by volume or percentage). The espresso with oils and sediment removed is very much recognizable as espresso and not any other form of coffee, but a little off. It's the bulk not only (and not most importantly) in volume, but also in taste. It needs the other components to fully be espresso, but it's by FAR the most major component.

Also note the fact that the espresso minus oils and sediment is still very recognizable as espresso says way more for the dissolved solids being the most important part than the oils and sediment not being recognizable as espresso says. It wouldn't say much of anything just knowing oils taste not like espresso without knowing that espresso is already pretty close to itself without them. Sediment is just self evidently not even close to the importance as you can just try making Turkish coffee and just putting coffee ground for making Turkish coffee in room temperature water and comparing them. Same sediment, clearly not as important as the extracted stuff.

Also dissolved solids are the only ones that really change taste by amount of extraction. Sediment is always just sediment, the oils are always just the coffee oils, but the dissolved solids change what's extracted based on the evenness and level of extraction. The quantity of sediment and oils is all that matters in the cup for those, you never get underextracted oils or underextracted sediment, but for the dissolved solids it matters what percent of them were removed from the coffee.

User avatar
AssafL

Postby AssafL » Feb 16, 2019, 7:28 am

So in the interest of trying to understand your point of Espresso being composed of water that tastes like espresso and lipids and dissolved solids -

Is that the same as saying an emulsion (say mayonnaise) does not taste like its components (egg yolk and oil and lemon juice and mustard) which may be oily and bitter and yucky?

Isn't the entire purpose of an emulsion to change the flavor delivery?

At least in Ice Cream I know the foam and oils and sugar protect the tongue from the cold and delivery the flavor in a somewhat attenuated format (hence making a cloyingly sweet base taste rather okay)?

Same as mayyonaise and even aioli transforms the flavor delivery.

I am looking for a way to substantiate the claim that it is okay to calculate EY not using Total solids but using TDS. And even if the claim is that it isn't perfect I'd be happy to have the errors identified and at least qualitatively estimated. Is it a mere 2-3% error in EY or is it 5-7%

Oh and please don't tell me it is 0.3%. That means a quantitative approach rather qualitative to even imagine that is true.
Scraping away (slowly) at the tyranny of biases and dogma.

CwD

Postby CwD » Feb 16, 2019, 7:41 am

AssafL wrote:
I am looking for a way to substantiate the claim that it is okay to calculate EY not using Total solids but using TDS. And even if the claim is that it isn't perfect I'd be happy to have the errors identified and at least qualitatively estimated. Is it a mere 2-3% error in EY or is it 5-7%

Oh and please don't tell me it is 0.3%. That means a quantitative approach rather qualitative to even imagine that is true.


Extraction. Yield. Is. Only. For. Extraction. Oils and sediment are part of coffee. They are not a part of the extraction process. Extraction yield is calculated with TDS because we are looking for EXTRACTION yield. That only describes how much of the dissolvable stuff in the coffee got dissolved. This isn't oils yield, it's not dry coffee yield, it's not total yield. It is ONLY extraction yield. Nothing else. It's like you're trying to say it's not ok to say something is 5 meters long if you don't know how much it weighs. It's measuring different things.

Which isn't a problem anyway since you can't under or overextract coffee oils or sediment. The sediment never gets bitter or sour. The oils never get bitter or sour. You don't have to worry about correctly extracting them. Only the dissolved solids get messed up based on what proportion of them were taken from the dry coffee. Be nice to know, but isn't as important. And, quite frankly, you're not going to be able to precisely dial in the amount of oils and sediment like you can dissolved solids with any normal espresso equipment, so less important and less useful.

And again, failing to filter still doesn't tell you the amount of oils or sediment in coffee anyway. You don't get to know dissolved+undissolved+oil, by failing to filter. You just get NONE of those things instead of only one of those things.

And the entire concept of qualitative error is absurd. This is an objective quantitative measurement. It's like trying to throw errors on your rulers for what objects kind of look like.

jpender

Postby jpender » Feb 16, 2019, 12:56 pm

CwD wrote:Suspended solids are an absurdly nonsensical way to track extraction for taste, just try pouring a bunch of ground coffee in cold water. 100% extraction yield off of a measure including suspended solids, taste like gritty water. Probably provide some texture, which is important, but they don't have much ability to be a major player taste wise.


No argument there. But you said that "tds alone is by far more useful than tds and suspended solids" and that's what I was questioning. It makes sense that TDS alone would be the better choice versus total solids but it could be that in practice it doesn't actually make much difference.

User avatar
AssafL

Postby AssafL » Feb 16, 2019, 2:54 pm

I may have confused some terms. I thiught extraction was "the part of the puck that found itself in the drink" and extraction yield was that expressed as percentage.

What you are suggesting is that the particulate and oils are not part of the extraction. (I originally thought the part that participates is the percolated part or the dissolved part and had nothing to do with extraction).

So why dehydrate pucks and coffee? Wouldn't a dehydrated coffee leave the particulates to give an erroneous EY since it includes stuff that wasn't "extracted" via the extraction process?
Scraping away (slowly) at the tyranny of biases and dogma.

CwD

Postby CwD » Feb 16, 2019, 3:42 pm

jpender wrote:No argument there. But you said that "tds alone is by far more useful than tds and suspended solids" and that's what I was questioning. It makes sense that TDS alone would be the better choice versus total solids but it could be that in practice it doesn't actually make much difference.

It's probably oftentimes close, especially with espresso where your sediment is pretty minimal, but occasionally breaks down entirely giving nonsense always 100% answers for certain brewing methods like Turkish or cupping.

AssafL wrote:I may have confused some terms. I thiught extraction was "the part of the puck that found itself in the drink" and extraction yield was that expressed as percentage.

What you are suggesting is that the particulate and oils are not part of the extraction. (I originally thought the part that participates is the percolated part or the dissolved part and had nothing to do with extraction).

So why dehydrate pucks and coffee? Wouldn't a dehydrated coffee leave the particulates to give an erroneous EY since it includes stuff that wasn't "extracted" via the extraction process?


Exactly. Particulate and oils are very much part of the coffee, but not of extraction, the process of the water dissolving the soluble parts of the coffee. The sediment and oils get moved mostly as they were. Neither fat or cellulose is water soluble, so isn't going to undergo any process with a gradient of quality like the dissolved solids do, but just being carried down as is.

Drying pucks is a good way to get total yield if done properly (controlled enough to not let evaporation carry away anything), and you can probably track relative extraction at least decently for internal use, but you won't know how much of the soluble part of the coffee specifically got removed from the puck that extraction yield through tds tells you. It's also generally less useful since you're not pinpointing the thing responsible for over or under extraction, or the only part you have real direct control over. Although sharing both extraction yield and total yield would be more descriptive to convey the experience. But if my difference between total yield and extraction yield doesn't match yours, I'm probably not dialing in to it unless I have a roller mill I can set to make X particles under Y and a dosing system that strategically positions them in the basket so the right amount get through the holes. It's like sharing your drink's pH. It probably effects taste somewhat, but if you can't control it, why bother measuring it?

User avatar
AssafL

Postby AssafL » Feb 16, 2019, 4:49 pm

CwD wrote:Neither fat or cellulose is water soluble, so isn't going to undergo any process with a gradient of quality like the dissolved solids do, but just being carried down as is.


Yes. Cellulose doesn't dissolve in water. I use it though as it binds with water forming a colloid. The colloid will obviously allow more particulate stay dispersed in the suspension.

In online searches n' (refractive index( is related linearly to the ratios of the dispersed to continuous phases. https://www.google.com/amp/s/www.resear ... rsions/amp

That would be one source of error that can be evaluated.
Scraping away (slowly) at the tyranny of biases and dogma.