Originally posted by MrJack
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Underextraction vs Overextraction!
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Yes, you're right, the chart shows a filter coffee and I should have stated so.
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Ah cool okay haha *fist pumps*, thanks mate.
And that makes sense that the TDS for espresso is much much higher compared to filter brewed coffee ,the filter brew would be less solubles (or moreso same/similar solubles extracted, but less concentration) based on the sheer amount of extra water used.
Now how to translate all this into useable practical knowledge haha, I'll research BH, they usually are pretty good with that
(I just wrote a whole bit and deleted about why I didn't understand why the chart was showing TDS to be higher for filter brews but didn't realise the percentages were 1.2%, thought it said 12% XD my bad!)
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Ahhh a little bit... have read these posts a few times over and I think I get it maybe haha.. I did understand bits of it, I'll have a look at the article, thanks so much for looking for me I do appreciate it.
So TDS is a ratio expressed as a percentage of espresso solubles (that which can be dissolved and taken away by the water) divided by the espresso mass itself, to get a percentage of all the dissolved solids within the beverage, ie the percentage in an espresso of the total dissolved solids relative to the total espresso mass extracted (ideally 8-12%?)?
Whereas extraction percentage is just the percentage of solubles extracted from the grounds (but leaving total espresso mass beverage out of it)....? )(ideally between 18-22%)?
Thanks everyone for all your help, I'm sure it'll click haha, whether it's something that will help me in espresso extractions or not I'm too not sure unless I had a refractometer... it is fascinating nevertheless!
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As I understand it, the brewing control chart was created based on experiments with brewed coffee - it's relevance to espresso taste preferences is questionable.
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In the classic definition, a double espresso would measure 60 ml volume. Because this includes crema, which has a far lower density than the actual liquid, this would be way less than 60 grams already. Since different coffees produce different amounts of crema, it makes more sense to define a shot by mass rather than volume. 18 grams of ground coffee "should" produce a 36 grams shot, but plenty of people gravitate towards a more concentrated version of espresso.Originally posted by saeco_user View PostI would have thought 18g is a double meaning the espresso shot will be closer to 60g hence the TDS is ballpark correct
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Is it starting to make sense Simon? I've been sifting through old BH and Jimseven posts to see if there's anything that could help you. The only one that really stuck out was this BH blog post - https://baristahustle.com/blogs/bari...cipes-strength The last section in particular, called "'The Perfect Strength' could be useful.Originally posted by simonsk8r View PostAh that's brilliant, thanks so much for that, will study that like crazy.
Hmm, I can understand how something can be underextracted and strong (stopping a shot really short, much less diluted), and overextracted but weak (a shot left going far too long), but the chart doesn't seem to be displaying that...
The green diagonal line seems to suggest that the longer you leave a shot the stronger it gets ad infinitum...
Also I've never quite understood the difference between TDS and extraction...
Total Dissolved Solids sounds like it should be what you're "extracting" from coffee (between the ideal 18-22%), yet it seems to be a different figure/equation altogether...
According to the graph, TDS seems to describe weak--->strong, whereas extraction seems to describe amount of flavour components in coffee as the shot progresses...
Am I on the right track in any sense at all? Haha...
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Yes, agreed, my maths was backwards.Originally posted by LeroyC View Post12% is the upper limit really of well made espresso. The range is along the lines of 8-12%. There would be a few exceptions. Let's pick one:
Sensory Lab for example recommend a brew ratio of 3:1 for espresso for some of their coffees. So in cases like this you're looking at -
20% extraction yield from 20g of coffee = 4g
4g in a 60g espresso = 6.6%.
To me that's about as low as you can go and still call it espresso. A good lungo extraction will be lower, but lungos are a fine art and aren't really true espresso so I won't include them.
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Spot on. Gee I wish I was able to explain things as well as that. I understand all that, but certainly couldn't put it into words like you have. This is all the stuff that the DE machine is delving into which is what makes it kind of exciting.Originally posted by MrJack View PostFYI - Espresso is WAAAY off the scale of that chart.
18 g (ground coffee) * 20% extracted = 3.6g (coffee dissolved)
3.6 g (coffee dissolved) / 30g (espresso) = 12% TDS
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In my opinion, extraction is one of the most misunderstood concepts in specialty coffee (second perhaps to the relationship between pressure and flow).
I think it is important to distinguish the extraction rate from the espresso flowrate:
- extraction rate is the rate mass is transferred from the coffee to the water in the basket.
- espresso flowrate is, rather obviously, the rate that mass is leaving the basket (water + coffee)
Why is this useful?
The ratio of extraction rate / espresso flowrate determines the concentration of the liquid leaving the basket at any given time. The average of this over the duration of the shot is equal to the mass extracted / espresso mass - which is the espresso concentration (i.e. TDS), as the calculation above demonstrates.
All else being equal, the extraction rate slows as the amount of soluble material left in the puck decreases (i.e. as the shot progresses). Meanwhile, the espresso flowrate increases at the same time. The net result is seemingly obvious - the concentration of the liquid leaving the basket decreases during the shot and the espresso concentration must decrease along with it.
But that isn't the whole story. We can't just dilute a ristretto to make an espresso, right?
Well, as I mentioned above, the extraction rate slows as the amount of soluble material in the puck is depleted. But not all components extract at the same rate. The dissolution rate of a given component likely depends its solubility and how much of it there is. Highly soluble components would therefore dissolve fastest (possibly completely) and would make up a greater part of the composition at the beginning of the shot. The less soluble compounds would dissolve at a slower rate but may make up a greater fraction of dissolved solids later in the shot.
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12% is the upper limit really of well made espresso. The range is along the lines of 8-12%. There would be a few exceptions. Let's pick one:Originally posted by saeco_user View PostI would have thought 18g is a double meaning the espresso shot will be closer to 60g hence the TDS is ballpark correct
Sensory Lab for example recommend a brew ratio of 3:1 for espresso for some of their coffees. So in cases like this you're looking at -
20% extraction yield from 20g of coffee = 4g
4g in a 60g espresso = 6.6%.
To me that's about as low as you can go and still call it espresso. A good lungo extraction will be lower, but lungos are a fine art and aren't really true espresso so I won't include them.
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I would have thought 18g is a double meaning the espresso shot will be closer to 60g hence the TDS is ballpark correctOriginally posted by MrJack View PostFYI - Espresso is WAAAY off the scale of that chart.
18 g (ground coffee) * 20% extracted = 3.6g (coffee dissolved)
3.6 g (coffee dissolved) / 30g (espresso) = 12% TDS
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FYI - Espresso is WAAAY off the scale of that chart.Originally posted by Leaf_Bean_Machine View PostYes, that's exactly right.
Use the following rules of thumb for espresso:
under extraction - shot is sour - flow too fast (and/or channelling), yield (shot volume) too low, bad tamper, water too cold
over extraction - shot is bitter/astringent - flow too slow, yield too high, water too hot
As it says, strength and extraction are related but not the same - you can have strong coffee that is under extracted and weak coffee that is over extracted - see the universal brewing control chart example here with these areas labelled.
18 g (ground coffee) * 20% extracted = 3.6g (coffee dissolved)
3.6 g (coffee dissolved) / 30g (espresso) = 12% TDS
-----
In my opinion, extraction is one of the most misunderstood concepts in specialty coffee (second perhaps to the relationship between pressure and flow).
I think it is important to distinguish the extraction rate from the espresso flowrate:
- extraction rate is the rate mass is transferred from the coffee to the water in the basket.
- espresso flowrate is, rather obviously, the rate that mass is leaving the basket (water + coffee)
Why is this useful?
The ratio of extraction rate / espresso flowrate determines the concentration of the liquid leaving the basket at any given time. The average of this over the duration of the shot is equal to the mass extracted / espresso mass - which is the espresso concentration (i.e. TDS), as the calculation above demonstrates.
All else being equal, the extraction rate slows as the amount of soluble material left in the puck decreases (i.e. as the shot progresses). Meanwhile, the espresso flowrate increases at the same time. The net result is seemingly obvious - the concentration of the liquid leaving the basket decreases during the shot and the espresso concentration must decrease along with it.
But that isn't the whole story. We can't just dilute a ristretto to make an espresso, right?
Well, as I mentioned above, the extraction rate slows as the amount of soluble material in the puck is depleted. But not all components extract at the same rate. The dissolution rate of a given component likely depends its solubility and how much of it there is. Highly soluble components would therefore dissolve fastest (possibly completely) and would make up a greater part of the composition at the beginning of the shot. The less soluble compounds would dissolve at a slower rate but may make up a greater fraction of dissolved solids later in the shot.
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Thanks Barry I've read that but will read through again, cheersOriginally posted by Barry O'Speedwagon View PostThe analysis at Home Barista in the link below is also very well explained:
https://www.home-barista.com/espress...tractions.html
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Thanks heaps Leroy, yeah I plan on buying that one for sure. Yeah BH I've found is great, yeah can get sometimes a little wordy, but overall I love everything it's about. Perger pulls no punches and isn't afraid of getting in there and experimenting and exploring all things coffee. I haven't seen many getting so involved and even his recent distribution tool project is awesome
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The analysis at Home Barista in the link below is also very well explained:
https://www.home-barista.com/espress...tractions.html
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