[MWJB]

15 bar extractions: unknown, but Nespresso claims their machines extract at 15 bars, and according to James Hoffman they're getting very high extractions, so this is an interesting avenue to explore.

Isn't that more a function of their longer brew ratios & grind distribution than blind bar pressure?

 

[MWJB]

I don't know, the only article I've found analyzing Nespresso is this one: http://www.jimseven.com/2015/05/21/an-analysis-of-nespresso-part-i/

If you have some links of others analyzing what's going on inside a Nespresso machine, I would love to read those!

I have also measured EY of a few Nespresso shots, not with the same amount of detail that James Hoffmann did. But notice that in his sieve tests of a Lungo capsule 80% of the ground weight was over 500um, filter coffee territory? The lungo I measured was 6.4g dose into 110g of beverage, or a 17:1 ratio in the cup (would equate to 19:1 as a drip ratio, so a bit lower than typical).

The pods I weighed were in the region of 5.1g dose to 6.4g dose, so even for a Nespresso 'ristretto' shot that's ~4:1 ratio, 6 or 7:1 ratio for Nespresso 'espresso'.

So it strikes me that the high yields are related more to the long brew ratios employed, the fact they still taste good into the mid 20's (I measured a lungo at 29%EY and it was bitter as you'd expect) probably more a function of the grind distribution (I have had sweet tasting mid 20's extractions from commercially ground coffee too).

 

[MWJB]

Good question, surely the flow rate must proportional to the dose & grind?

Probably more of a relationship to brew ratio (assuming a common grinder).

 

[MWJB]

Wouldn't this be very difficult to achieve even with most pressure profile machines? My understanding is that it is the combination of pressure profiling, the bluetooth scales and the programming which enable this machine to adjust to achieve a steady flow rate so the only way I know of to easily try this is to buy one of these and experiment. I've had a go at adjusting mine to steady the flow but I guess it probably requires continual adjustments rather than a few stepped changes.

All machines & shots have flow rate, in the respect of a given shot weight over so many seconds of total shot time, this machine & the Acaia scales are exciting from the aspect that they can really show how the flow changes & and can be manipulated, but is there anything out there to say that a steady flow is more/less desirable, or a historical precedent?

 

[MWJB]

I have no idea. Although initially you might logically think that a steady flow rate would result in more even extraction, as extraction rate changes with contact with water (i.e. slows as more solids dissolve) presumably an increased flow might result in more even extraction over the length of a shot? I guess this machine would make such experiments relatively simple as you can ask the machine to target a flow profile, level or otherwise?

I can't see the mechanism as to how a constant flow rate (still though, what would it be & how would the requirement change in the real world?) would make a more even shot, but that doesn't mean it can't happen My gut says decaying flow rate would be useful (I won't say "better"), slower flow as solids become harder to extract, easier to kill shot at target weight (but sometimes my gut just makes odd noises, so I don't listen that hard)? Grind distribution & good preinfusion still seem to be most likely candidates here?

Indeed, it's an exciting prospect.

 

[MWJB]

Do they pay UK Tax and give jobs to UK people?

Is that a sensible question to ask in the context of coffee generally & European/Chinese machine, grinder & accessory manufacturers?

 

[MWJB]

And I'd love to know how long a drop of water stays in contact with the puck. Other than chemically marking the water, I'm unsure how to figure that out.

How accurate would you really need to be? If the machine tells you the puck is saturated at the end of preinfusion, then any more liquid pushed in, must come out the other side. You could work out over shot time vs weight in the cup, how long it takes to exchange a full puck's worth of liquid, factor in EY against puck erosion too for a full puck prior to flow vs end of shot.

Even without the data you have access to, a rule of thumb would be that a 16:32g shot over 36sec saw the liquid in the puck exchanged once every 18sec on average.

 

[MWJB]

Pre-infusion or preinfusion?

It is not-so-helpfully spelled 3 different ways in its definition at Coffee Geek:

http://coffeegeek.com/opinions/markprince/07-20-2004

Pre Infusion: the act of pre-wetting the bed of ground coffee inside an espresso machine before actually commencing the brew. Some espresso machines do this by using the pump; water is pumped to the coffee for a second or two, then halted for another second or two. After this pause, the pump activates again, and continues brewing the shot. Super automatics and some automatic machines use this pre-infusion.

Another type of preinfusion is called "natural" or progressive preinfusion, and occurs in machines equipped with an E61 grouphead. When the pump is activated, a secondary chamber must fill prior to full pressure being applied to the bed of coffee. This gives a 3 to 7 second saturation time for the grounds before the pressure builds up. This type of preinfusion is preferable to pump and pause active preinfusion.

Seems to just be a preference issue, or pre-ference? Both preinfusion & pre-infusion are legit.

 

[MWJB]

I vote for "extraction."

The liquid at the bottom of the puck will already have extracted a significant amount. Of course, there is nothing/next to nothing in the cup at this point, so no extract to show...I could be guilty of a 'distinction without a difference'

How about "flow".

 

[MWJB]

How does it compare to a Chemex/Kalita taste and sludge-wise? I am wondering, because the DE can obviously not emulate the circular or targeted ("oh a dark spot in the grounds") motions necessary to do a pour-over.

You don't need to target specific areas to do a pourover, especially not if you have a shower screen, nor if you add all the water quickly in one go after bloom.

 

[MWJB]

I haven't tasted the method with the aeropress filter in thr DE1 yet, but I do know that pressure increases the micro-fines which get past the paper filter in the aeropress. So I assume it won't be as clear as a gravity filter method.

You can have gravity percolation without paper, like a Swissgold or Kone brew.

Aeropress is an immersion method, with a tiny bit of percolation at the end. Espresso & drip/pourover/filter are percolation & produce a higher strength at the same brew ratio & extraction. This is why you might see a gadget to increase crema on an Aeropress to make it more 'espresso like' but it'll never be espresso if you have the entire brew water sit with the coffee dose like it does in an AP. You can make espresso at 12%TDS or more, you can't make Aeropress at more than half of that, whatever the ratio you use.

 

[MWJB]

This is about a 1.35% TDS "coffee shot" with a paper filter versus a pour over at the same TDS. The big money question is can a reasonable approximation of a V60 be done by the DE1 with the advanced program.

This sounds over-extracted. Compared to V60 the target would be more like 1.11%TDS +/-0.15%.

Sure, you should be able to get a well extracted cup...don't know if it would taste exactly like 'a V60' as people make them differently, different filters (Dutch, Japanese, paper, wire mesh...).

 

[MWJB]

I make my V60 at 1:16.7 at 1.38% TDS 30g:500g with an EK43 which is 21.4% extraction. 1.45% (22.5%) isn't bitter but some flavours over power the rest.

1:18 in the cup, as per the video, is more like a 1:20 V60 brew.

 

[MWJB]

The only company that has ever done this was La Marzocco I believe and it was purely for experiments not for actual shots.

You would have to have both a transparent PF as well as a transparent basket. The chances of anyone doing this in any kind of practical way for a tiny market of people who might want them is slim to none.

It was La Spaziale

[video=youtube;-Xmq8NqdUiM]

 

[MWJB]

James Hoffmann's video, for example, specifically calls out that he is careful about the kind of water he puts in any espresso machine.

This is obviously an important issue, so really you need to specify what 'being careful' & 'good water' are, in terms that the user can relate directly to the labels on the bottles.

 

[MWJB]

I think good advice is "We always recommend you use bottled water with a Ca below 'X' (as you get some hard bottled waters) but tap water can be ok if you know you live in a soft water area. A good way to tell is by looking in your kettle, if you see calcium build up your water is probably a bit too hard, if not your probably ok."

At least, it's a very broad way of telling if you should be being careful, I dont know how accurate a piece of advice it is. I can tell you that I never see calcium build up in Kettles around here, even after years.

It's not great advice because some areas have high magnesium (Mg).

If you do have scale in the kettle, then what do you do? Most bottled water is hard too. Just to throw a spanner in the works, my parent's kettle is clean but they have 100mg/L Ca and nearly 300mg/L bicarbonate (hard).

Basically, assuming your water is reasonably normal, the bicarbonate/alkalinity is a better guide. It's on bottled water labels & can also be supplied by the local water authority:

50-75mg/L as bicarbonate (as per bottled water label).

40-60mg/L alkalinity as CaCO3.

...would be a good target.

 

[MWJB]

This is the Volvic ever popular bottled water in the 8ltr self seal top, I think Mark commented it was slightly lacking and needed something adding to bring it into the range of being the ideal.

Jon.

Jon.

74mg/L Bicarbonate is in the healthy range. Volvic is one of the very few single bottle options.

 

[MWJB]

A paper filter at the bottom, another filter (= barrier) at the top, a blooming phase, then 2 bar - sounds like an Aeropress to me

60lb of plunge pressure?

 

[MWJB]

https://www.coffeeforums.co.uk/index.php?app=core&module=system&controller=embed&url=https://www.instagram.com/p/Bh_eHO_DohP/?hl=en

Whilst they don't actually know whether the VST "undershot" the TDS readings (moisture balance used was no more precise than the VST refractometer & there was no dehydration datum for accuracy), the HM had the widest spread of readings & average was different to VST & Atago by a fair margin.

 

[MWJB]

Well, they filtered the instant, probably safer than them brewing it.