Slayer single group review - Page 5

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shadowfax
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#41: Post by shadowfax »

Peppersass wrote:Unmodified GS/3 volumetric or MP: Not much different from any other high-quality machine.

Strada-style pressure profiling: Can smooth harsh/sour/vegetal flavors of light-roasted coffees.

Slayer-style low-flow pre-infusion: Makes the flavors of light-roasted coffees really pop.
I pretty much agree with this. I assume most people who are following the Slayer and any other 'profiling' machine are familiar with this thread about the pressure/flow profiling 'rule of thirds,' where I explained a significant part of why I decided to eschew the full control over shot pressure I have with my modified LM Shot Brewer and buy the Slayer in the first place.

After I made the tweaks to my shot brewer to get the inlet pressure down to around 20 psi, I was able to, albeit slightly inconsistently, approximate what the Slayer does as far as flow and pressure delivery. My setup is simlar to Dick's modified GS/3 AV, but a bit better inasmuch as I can play with much longer shot times, and also use the paddle to (inconsistently, again) add a dimension of initial flow restriction in. I love that machine, and it allows you to do fun, awesome things with espresso. It's also more work, sensitive to inattention, and doesn't make cappuccinos. I didn't realize how much I would miss those! :lol:

The Slayer doesn't perform very differently from that setup, to be honest. You can tighten the flow restriction much further (to the nth degree, literally), which allows/forces you to grind even finer for a given dose-not that there is much use to this: I haven't found any utility to going below 1 g/s of initial water debit. The Slayer's 'magic,' if it has any, is providing an easy, repeatable way to control this crucial dimension of shot adjustment, delivering what I think is most of the useful potential of pressure/flow profiling with just a needle valve (which is generally adjusted only occasionally) and glorified 3-position switch.

Just to touch briefly on how the espresso tastes with the Slayer: recently, I brewed some George Howell Panama La Esmeralda Mario San Jose on the Slayer. The first shot was good, but it took me till the second one to have it dialed in. The shots were bracingly delicious, syrupy orange flower honey delicacies. I've also reviewed the Chicago Trio on the Slayer (C1, C2, C3). Those cover a little bit of when to use the slow 'pre-brew' of 'Slayer-style' shots, and when not to. It is quite capable of producing excellent espresso with ease. My impression of the Slayer is that its extra control is very useful for pulling very bright, light-roasted coffees as espresso (a la Dick's comment above). For more traditional espresso roasts, I'd be hard-pressed to say it adds much that you couldn't get with a GS/3 or similar machine.
Nicholas Lundgaard

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another_jim
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#42: Post by another_jim »

I don't have Slayer, but use a lever, and have had many profiled shots in cafes. My take is similar to Peppersass's and Shadowfax's: light roasts of higher grown coffee have a much narrower margin of error than more conventional roasts. I think the longer preinfusions, declining pressures, and longer shots enlarge the forgiveness factor.

There is old data from Illy that suggest that it is easier to get highly extracted shots from darker roasts. Moreover, it is usually good practice to grind coarser for darker roasts. The Extract Mojo fans suggest these data are an artifact from not distinguishing total solids in the cup from dissolved solids; but what if these data are true? What if it is a whole lot harder to fully extract light roasts, and that they require finer grinds for pour over, and longer shots for espresso? That would make sense of both the profiling data in espresso making, and the trend towards finer grinds in brewing.
Jim Schulman

caffeinezombie
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#43: Post by caffeinezombie »

indend007 wrote:Removed so as not to spam
Your set up is really interesting! Care to share more on what it looks like internally?

Bob

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Peppersass
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#44: Post by Peppersass »

another_jim wrote:There is old data from Illy that suggest that it is easier to get highly extracted shots from darker roasts. Moreover, it is usually good practice to grind coarser for darker roasts. The Extract Mojo fans suggest these data are an artifact from not distinguishing total solids in the cup from dissolved solids; but what if these data are true? What if it is a whole lot harder to fully extract light roasts, and that they require finer grinds for pour over, and longer shots for espresso? That would make sense of both the profiling data in espresso making, and the trend towards finer grinds in brewing.
It surprises me to hear that it's not commonly agreed that darker roasts extract more easily than lighter roasts, and that we have to refer to old data from Illy to establish that fact. Haven't we always known this? Isn't it everyone's experience that coffee prepared from dark roasts is often bitter (think over-extracted Starbucks brew) and that coffee prepared from very light roasts is often sour (think under-extracted third-wave cafe brews)?

Seems to me the new info is that brewing techniques are emerging to extract more from light roasts.

Also, I don't recall seeing arguments from VST fans denying that darker roasts extract more easily than lighter roasts. Can anyone point me to those posts? The VST system makes no assumptions about the roast level or extraction rate of the coffee. And it doesn't know how fine you're grinding, how long you run shots or steep, or what the temperature or pressure are. All those variables affect the extraction yield, but they're external to the calculations. AFAIK, people who dehydrate coffee and dry spent grounds in an oven to do similar measurements and calculations don't make assumptions about those external variables, either.

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NoStream
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#45: Post by NoStream »

As a refractometer enthusiast, it seems really obvious that darker roasts tend to be more extractable. And roasts without proper development struggle to extract - especially as espresso. But even comparing a perfectly-executed ultra-light roast to, say, a full-city roast, the darker one will extract better. (And certain coffees tend to be more extractable due to the green coffee itself, presumably on account of density or some other factor.) I assumed this was considered common knowledge.

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nickw
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#46: Post by nickw »

Re: dark roasts extracting better.... To clarify, are you meaning the beans are more soluble, or at least the elements which we wish to desire?

Either way: I think it's more that that. The balance of the bean has changed (less acidity, more sweetness/caramelization [until it starts burning]), so what we desire to extract from the bean changes. Thus the extraction method. Which is why we tend to overdose and under extract darker roasts (for reasons discussed by Dick).


BTW: Shadowfax, I did read your thread on the first 1/3 or extraction. Found it fascinating.

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another_jim
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#47: Post by another_jim »

NoStream wrote:As a refractometer enthusiast, it seems really obvious that darker roasts tend to be more extractable. And roasts without proper development struggle to extract - especially as espresso.
The articles in Illy are literature reviews (which is why the book is so valuable). The espresso article gives extraction ranges of 20% to 25% depending on roast level. These data were contested by Andy Schechter, who was relaying the research and conclusions of Vine Fedele who claimed that these differences were based on total, not dissolved solids.

But this is a side issue. The main issue is that if light roasted coffees are harder to fully extract than dark roasted, they represent more of a technical challenge for espresso making (and pour over).
Peppersass wrote:Isn't it everyone's experience that coffee prepared from dark roasts is often bitter (think over-extracted Starbucks brew) and that coffee prepared from very light roasts is often sour (think under-extracted third-wave cafe brews)?


This piece of conventional wisdom needs to be rethought as well.

You can get bitter tastes from cooking coffee, whether roasted light or dark (think instant coffee, or forever on the hotplate coffee). This is not overextraction, but a product of extracting too long or too hot or both. A light or medium roast done for 40 seconds on an HX machine will be cooked-bitter in this way.

In a dark roast, the caramels are more bitter than sweet, and they extract slowly and add to the bitterness. These same caramels, extracting at the same rate, simple add buffering and sweetness to lightly roasted coffees, so that full extractions tend to taste milder than under extractions. Finally, light roasts have "bright-bitter" compounds reminiscent of lemon zest, orange peel, or the digestive bitters like Campari, Fernet Branca, or quinine tonics. These extract quickly and need to be buffered by the milder caramels that extract slowly.
Jim Schulman

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shadowfax
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#48: Post by shadowfax »

another_jim wrote:In a dark roast, the caramels are more bitter than sweet, and they extract slowly and add to the bitterness. These same caramels, extracting at the same rate, simple add buffering and sweetness to lightly roasted coffees, so that full extractions tend to taste milder than under extractions. Finally, light roasts have "bright-bitter" compounds reminiscent of lemon zest, orange peel, or the digestive bitters like Campari, Fernet Branca, or quinine tonics. These extract quickly and need to be buffered by the milder caramels that extract slowly.
Really interesting stuff. This helps conceptualize why the Slayer's 'pre-brew' works so well at extracting these dense, light-roasted coffees that I am enjoying. With these coffees, a the long contact time and hot water serve primarily to amplify the sweetness and give balance, while also (to a lesser extent) intensifying the bright notes-hence why shots of this type of coffee brewed in this fashion really "pop" and also tend to have a candied sweetness to them.
Nicholas Lundgaard

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Peppersass
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#49: Post by Peppersass »

another_jim wrote:This piece of conventional wisdom needs to be rethought as well.

You can get bitter tastes from cooking coffee, whether roasted light or dark (think instant coffee, or forever on the hotplate coffee. This is ot overextraction, but a product of extracting too long or too hot or both. A light or medium roast done for 40 seconds on an HX machine will be cooked-bitter in this way.
First, my post may not have been clear enough. It sort of sounds like I said dark-roasted coffees are always bitter and light-roasted coffees are always sour. I meant to say that roasting and brewing mistakes frequently cause cups from dark roasts to be bitter and cups from light roasts to be sour. In the case of dark coffees, over-roasting will do it, as will grinding too fine, running/steeping too long, etc. In the case of light coffees, under-roasting (under-developing) will do it, as will grinding too coarse, running/steeping too short, etc.

Second, it would be nice to know the mechanism that's at work when a coffee is cooked. Is it that undesirable compounds are extracted when the water is hotter, or is it that compounds actually change in structure (like amino acids shriveling up when meat is over-cooked)? Has this been determined?

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another_jim
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#50: Post by another_jim »

Peppersass wrote: Is it that undesirable compounds are extracted when the water is hotter, or is it that compounds actually change in structure (like amino acids shriveling up when meat is over-cooked)? Has this been determined?
I'm not aware of any literature; but it's almost certainly the latter:
  • Coffee on a hot plate is not extracting, but is getting bitterer
  • The insolubles in coffee are long chain polymers, like cellulose, which are tasteless. When these are cracked when making soluble coffee, it is done at high pressure and temperature. This "overextraction" is via chemical breakdown.
Jim Schulman