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I have a query I'd like to hear peoples thoughts on:

If you are dialling in a new coffee for espresso, and you go, say, 18g in 36g out (1:2) in 22 seconds, you decide you need to slow the shot down.

In hypothetical scenario A you keep the dose at 18g and tighten the grind a bit finer, and the 36g shot (1:2) comes out in 30 secs.

In hypothetical scenario B you keep the grind the same but up the dose to 19.5g and get a 39g shot (1:2), also in 30 secs.

What are the extraction or taste differences between the two shots?

[I realise that the advice is generally to "lock in" your dose and only adjust the grind, bit this is to help me try to understand extraction a bit better]

Ta!

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I always adjust grind first. If after a few shots I start getting close (in terms of taste, not necessarily time) then I may tweak the dose by .5 gram 

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LR, ZM

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I'd imagine that a lot of people here would adjust grind size and have a locked dose. Personally, I work on 18g dose for a standard 1:2 yield to start, and taste if it's under/over extracted (bitter/sour). From there, I'll decide if I need to increase shot time and grind coarser for a less bland coffee (am I getting all flavour notes etc.?), I'd then decide if I need to change the dose by half a gram or so. The below infographic is what I use:

Image result for espresso taste chart

I tend to stick to a 1:2 ratio, as I'm not 100% sure on what increasing/decreasing ratios do apart from on the dark roast or light roasted side (increased for light roast). But I also tend to increase temperature on light roasted coffee for more extraction, and decrease for particularly dark beans. If I have a balanced coffee at 1:2 ratio with decent mouthfeel then I don't see much of a reason to mess about with ratios (I'm sure someone here can explain why I should or shouldn't though, and would be glad for someone to explain to me!).

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This gets quoted a lot too

 

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LR, ZM

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Thanks very much! Cooffe I feel happy with the "up/down" portion of your diagram, I guess that the "right/left" portion answers my question - if your 1:2 30sec coffee is 'too aggressive' go for Hypothetical Scenario A (tighter grind, lower dose), and if it's 'too bland' go for Hypothetical Scenario B (coarser grind, higher dose).

Using the correct terminology, does "too band" = underextracted, and "too aggressive" = overextracted?

I sometimes look at the Barista Hustle extraction compass.

Screenshot_20190820-211119.png

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@CoolingFlush I think the too bland/too aggressive can also be described as other things such as "Hollow/Empty" or "Thin" (Similar to the words used in the red portions on the bottom of the graph you posted). The aggressive would be overpowering - maybe leaving a very prominent aftertaste etc. 

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3 hours ago, CoolingFlush said:

Thanks very much! Cooffe I feel happy with the "up/down" portion of your diagram, I guess that the "right/left" portion answers my question - if your 1:2 30sec coffee is 'too aggressive' go for Hypothetical Scenario A (tighter grind, lower dose), and if it's 'too bland' go for Hypothetical Scenario B (coarser grind, higher dose).

Using the correct terminology, does "too band" = underextracted, and "too aggressive" = overextracted?

 

Too bland/aggressive relate more to strength than extraction.

Strength & extraction are loosely related & only tie up at the same brew ratio. (E.g. you can brew coffee to 18%-21% extraction at a typical strength for any brew method, filter/brewed will be weaker than espresso but extraction can be the same, as it does not depend on the amount of water in the cup, just the ratio of dissolved coffee vs dose).

What's your fascination with 30s? In your earlier post 18g dose & 19.5g dose, both at 1:2 & same extraction would be pretty much impossible to tell apart by taste, assuming no other malfunction. 30s shots don't guarantee any specific level of extraction, your grind size determines extraction (all else being the same), shot time need not be so precise...in fact sticking to, say 30s 1:2, will cause your extractions to vary by a large margin.

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Thanks folks,

I started thinking more about this stuff when I changed from many years of using a "typical" pump driven 58mm machine, to a Pontevecchio Lusso with a 48mm Portafilter, and a spring lever requiring multiple pulls - the acquisition of this machine basically detonated two of my variables, dose and time. In actual fact I no longer time my output. As I've been dialling in various coffees (bright Ethiopians, blackened Italians, middling Brazilians) I've had to explore more , on all variables. Ultimately taste is king, and I'll be guided by that, but I'm trying to make sense of it all as I go.😋

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2 hours ago, CoolingFlush said:

Ultimately taste is king, and I'll be guided by that, but I'm trying to make sense of it all as I go.😋

Taste is king indeed, but when it is king awful you need to know which tangible thing to change to get you back on track ASAP (hint, it's grind & if that doesn't do it by itself, go longer on ratio). Taste is the result/output and can only be assessed after dealing with the inputs.

Drank a fair bit of mass market Italian/Euro espresso on holiday the other week (though not in Italy). Toasty perhaps, more than roasty, medium roasts more than very dark (had a 'filter' roast that was no lighter).


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Somewhat off topic but just noted @MWJB 's post count has hit 8000. I'd just like to thank Mark for his invaluable contribution to this forum.

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1 hour ago, MWJB said:

(hint, it's grind & if that doesn't do it by itself, go longer on ratio).

Thanks, I might have to try venturing into The Third Pull on my lever, to see what I get. I tend to favour short ratio, strong shots, but they are coming out a bit bright. I'll see if I get any more bitterness for balance, with a third pull.

1 hour ago, MWJB said:

Drank a fair bit of mass market Italian/Euro espresso on holiday the other week

I've been dabbling with it at home. Whilst that taste was once my baseline for What Espresso Tastes Like, I haven't enjoyed it as much as I remembered. I think my current baseline or reference point for espresso is a fresh, medium roasted Brazilian (either SO or blend) from my local roaster. 🇧🇷🍊🌶️

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I came across another BH piece discussing dose size, but this time in terms of puck depth. 

It suggests that increasing depth has a negative effect on 'vertical' temperature stability within a shot, and subsequent evenness of extraction.

It then suggests that although a more shallow puck counteracts this and allows you to grind finer, it is more at risk of channelling.

Their summary is: ”So the ideal dose is essentially the lowest you can use before channelling becomes an issue. Where that point lies depends on many things such as your grinder, your technique, and the brew pressure.”

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Really interesting point on temperature gradient. 

My thinking on the dose is that flow rate is proportional to pressure gradient, so a deeper puck with the same pump pressure means a smaller pressure gradient therefore slower flow. Which means more extraction per gram of yield since the same mass of water will spend longer in contact with the puck.

So an 18 to 36 shot will mean less extraction than 21 to 42. Despite the same yield.

Which I guess is why the recommendation is to coarsen grind at the same time (to increase flow and restore contact time/extraction?)

Having said that I read the BH blog series and still don't have a clear understanding of strength v extraction. Extraction is total volume of coffee removed from the puck, strength is concentration of removed coffee in the water? So I think I'm right in using the word extraction.

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1 hour ago, Michael87 said:

Really interesting point on temperature gradient. 

My thinking on the dose is that flow rate is proportional to pressure gradient, so a deeper puck with the same pump pressure means a smaller pressure gradient therefore slower flow. Which means more extraction per gram of yield since the same mass of water will spend longer in contact with the puck.

So an 18 to 36 shot will mean less extraction than 21 to 42. Despite the same yield.

 

Contact time (whatever that is) doesn't drive extraction. Grind setting does, it has a knock on effect on shot time (which is different to contact time).

If you had a basket that can accommodate 18g & 21g without malfunction, your range of extraction won't significantly be different for 1:2 shots.

If you under, or overfill the basket, your extraction will drop. There doesn't seem to be a universal problem in extracting 18g doses.


“Coffee evokes the most insane reactions in people”, Rene Redzepi.

 

https://markwjburness.wordpress.com/

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8 hours ago, MWJB said:

Contact time (whatever that is) doesn't drive extraction. Grind setting does, it has a knock on effect on shot time (which is different to contact time).

If you had a basket that can accommodate 18g & 21g without malfunction, your range of extraction won't significantly be different for 1:2 shots.

If you under, or overfill the basket, your extraction will drop. There doesn't seem to be a universal problem in extracting 18g doses.

By contact time I meant the time that it takes a small bit of water to travel through the puck, and hence is in contact with the coffee. Surely if that time is longer, the water has more opportunity to dissolve and take on coffee particles? I'm not sure that's right... but can't see why this might not be true.

Maybe I am imagining the extraction wrongly? (I'm picturing water being pushed through a porous solid object and soluable coffee particles diffusing from the solid into the water at the (tiny) boundaries, so that more contact time = more diffusion). 

 

Edited by Michael87

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Surface area (grind) will affect the water/coffee contact, time is a by product.


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44 minutes ago, Michael87 said:

By contact time I meant the time that it takes a small bit of water to travel through the puck, and hence is in contact with the coffee. Surely if that time is longer, the water has more opportunity to dissolve and take on coffee particles? I'm not sure that's right... but can't see why this might not be true.

Maybe I am imagining the extraction wrongly? (I'm picturing water being pushed through a porous solid object and soluable coffee particles diffusing from the solid into the water at the (tiny) boundaries, so that more contact time = more diffusion). 

 

I understand the concept of contact time, I don't recall anyone describing it in the terms you have used before I did so several years ago. But here's the problem - Your contact time for a 1:2 shot is an average of 10s, how are you monitoring this mid shot, or as the shot progresses? How is it helping you to pull the shot in real time? Total shot time is the most practical thing to measure, then you back calculate contact time.

If you extend time (be it contact or total time), your shots will start tasting bad before extraction significantly rises (too much silt in the cup due to too fine a grind) & even if your shots take a full minute extraction isn't going to massively rise compared to a 35s shot (same beans, same grinder). Your bad tasting shots may never over-extract.

Let's say your average shot time is 30s, +/-3s for a given grinder, or bean. Change grinder and your average might shift a % down, but shot time might increase by 10s. Change beans, same grinder and the average extraction might stay the same (+/-2% tolerance) but shot time change by 8s faster.

Shot time/contact time, once identified, is not meaningful enough to be useful in the espresso universe. It's only of some limited use for a narrow range of circumstances, or if you just pull the same blend/bean, at the same ratio, with the same grinder all the time.

Still the most practical way to know what your extraction is, is to actually measure it. You'll likely find that extraction will more closely follow grind setting & be normalised by fairly small adjustments. Differences in origin will decide the tolerance on extraction if your sample is big enough.

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To answer the original question 

IF all things are equal in theory your shots should be pretty similar BUT espresso is a fragile process with inconsistencies produced by man and machine . There is no guarantee you ever prep the basket the same way or that a grinder will shatter beans the same way two times running. 

You can measure a extraction by extraction yield but even two shots with the same EY could/maybe/can be perceived to taste differently . 

The points re flow made from BH etc. all good in theory but again not sure how anyone can actually measure or impact them. 

Time contact or shot time is again not something I Would be using to drive my shot by, especially across a range of coffee , as it is not an indicator or strength or extraction . 

 

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I think a lot of the information such has been mentioned is an attempt to apply science to espresso machines. I say machines to avoid types of drinks. People try to establish some rule when in practice there isn't a definitive one. The final result is taste and that is subjective and the ideal will vary from person to person.

It's all pretty simple. Unusually perhaps I use a fixed shot time but taste in the order of max impact is as follows. I do weigh what actually comes out.

Type of bean, grind, ratio

Beans can vary dramatically in taste. The grind primarily sets taste but some variation in ratio will be acceptable. Many people weigh out. In that case some variation in time will be acceptable.

This in real terms covers balancing the flavour to what the bean should have but leaves one other area. How strong the taste is. That is controlled mainly by the weight of grinds that are used but there can be other effect that aren't so straight forward. Grind too obviously. At some strength of taste more subtle ones may be masked by a dominant one. I generally drink americano and that effect can be rather noticeable on some beans. An espresso drinker might add water to open out the flavours as they might put it. Putting the same bean in milk can change the taste from say an americano to such an extent that it may taste like a different bean.

Beans may age and need changes to the grinder setting. Reasonable grinders seem to be pretty consistent in terms of what comes out. As most people aren't doing a to b comparisons as the beans age they might not notice subtle taste changes. Same with n shots a day really.

That just leaves grinds  preparation. Very probably the main cause of variations. My beans and my mouth suggest that shorter shot times for the same ratio have the worst effect and that shot time can be extended to some extent. At some point the grinder needs resetting. Variations in prep will change ratios.

That just leaves what ratio. The above is used to vary that. :) The web invariably mentions 1 to 2. Personally I think that can be the worst advice out there. Maybe it will prove more usable when I change machine but it's often way off with the ones I have used. My mouth and my beans again. A new bean I am currently using may work out best at circa 1 to 2. I've wasted several shots as for some reason the grinder has been putting out troublesome clumps. They are clearing now so results are more meaningful and something like 1 to 2 came out but I'll still try others.

John

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Makes lots of practical sense and sorry for the slight hijack. I'm really curious about the micro process of extraction, equations and stuff, but appreciate it is very hard to relate these things to practical measurements that good baristas use to make tasty coffee!

Edited by Michael87

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17 minutes ago, Michael87 said:

Makes lots of practical sense and sorry for the slight hijack. I'm really curious about the micro process of extraction, equations and stuff, but appreciate it is very hard to relate these things to practical measurements that good baristas use to make tasty coffee!

There's no harm in that but I feel that people can get carried away with it and if they don't try variations in what they do what ever that is they can't in real terms be aware of what they might achieve.

It's best to take advice what ever it is even mine and form your own conclusions. There are all sorts of approaches out there to all aspects of making coffee.

John

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1:2 is not the worst advice out there. it gives a chance of decent extraction and strength .there is a Reason why its quoted alot across  the coffee industry

where it falls down is when people misunderstood what a brew ratio is, how it drives strength and extraction and then how to adjust if said strength and balance is lacking . 


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Extraction isn't related to espresso machines specifically, it relates to all brewing methods (which all boil down to grinding up beans and flushing with/soaking in water). No method can use time to guarantee a certain level of extraction.

Yes, beans vary dramatically in taste - they're supposed to. :-)


“Coffee evokes the most insane reactions in people”, Rene Redzepi.

 

https://markwjburness.wordpress.com/

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42 minutes ago, CoolingFlush said:

Another one from James Hoffman: "coffee is a moving target"😎

Not really, more like adjusting for windage & elevation on a fixed target, rather than downing a bird in flight.

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“Coffee evokes the most insane reactions in people”, Rene Redzepi.

 

https://markwjburness.wordpress.com/

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