Spitz.me wrote: I remember Mark Prince tweeting about how water dilution works great for his spirits, but not so much for his espresso. Might be that I've pulled his sentiment out of context

I think people might be reading past my main point; I'm not making mini-americanos, I'm testing the idea that this effect is not linear, not based on dilution, extraction, or watering down; but a non-linear chemical change triggered by a few drops of water.

It is a mistake to think adding water only applies to barrel strength whisky, and that it is about diluting it to bottle strengh. The tradition with spirits is to add a drop or two of water. First off, this will not dilute a 50% or 55% barrel strength spirits to 40% bottle strength; second, it is done to 40% tequilas, scotches and brandies as well as over-strength bourbons. It is not about dilution, but about "opening up" the taste. This effect, if it exists, is highly non-linear, some sort of tipping process.

The speculation I read was that there is a change from the flavor molecules being bound up in covalent chains with van-der-wals bonds into them becoming available as shorter electrovalently bound molecules (I have no idea if this is right).

Since the blonde part of the espresso pour is basically water; going from a properly extracted ristretto to lungo should be a gradual dilution effect, and very tractable in terms of the taste changes. In the other hread, there were some people who insisted that this is not the case, that the taste change are sudden and large. The experiments I'm describing here seem to support their claim, at least for some coffees.

I personally like to think that the simplest answer is best. Your espresso tastes better with a bit of water because the dilution scales back the intensity of the espresso and allows your tongue to concentrate better on the different flavours. I believe this is akin to the idea of a "bliss point", where enjoyment is highest when the stimulus is neither too strong nor too weak. In the case of coffee, there are several bliss points (variable based on the coffee), which are in the two typical enjoyment range: espresso strength and regular coffee strength. Dilute a bit too much and you create an espresso that's too watery. Dilute even more and you create an americano that's too strong.

Now what water do you say we add? Preferably the kind that is sourced from the same finca as the beans, of course!

1 drop is roughly 1/10 gram, or 1 part in 200 of the 20 gram espresso. To say I can taste dilution seems more impossible than simple. The effect is either imaginary (i.e. because I'm not blind tasting) or due to a tipping point mechanism that strongly amplifies small changes. The tipping point mechanism is well attested in spirits; so it is not all that unlikely in espresso.

I would think the simplest explanation might be that if one is dealing with multiple strong flavors, the perceptual balance between them is much more unstable than with the same flavors at a weaker level. Think how much more delicate an equilibrium of very strong forces is versus very weak ones. Since the rate of flavor change to concentration change is different for different compounds, a drop of water or two could make a much larger difference when flavors are strong than when they are weak.

another_jim wrote:If the taste of the flow as the espresso blondes is neutral; how can stopping the shot be critical? But there is lots of anecdotal evidence that changing the brew ratio slightly can create large changes in taste.

I thought different brew ratios are achieved by changing the grind to allow more or less water through the same dose of coffee in a given time (as opposed to changing the amount of blonding allowed)?

My understanding is that coffee extracts differently as the grind is changed (I believe a coarser grind will be more overextracted than a finer grind as there is less surface area to be extracted and more water will pass through the basket).

If this is true, how can adding small amounts of distilled water be equivalent to changing the brew ratio.

Actually, brew ratios are what they sound like: a ratio of your brew. Specifically, your brewed espresso weight divided by your coffee dose.

I thought I would change brew ratios by changing the grind setting aiming to get the ratio I want in a set 25-30 seconds (for starters as the shorter or longer times may achieve better results).

It sounds vaguely reminiscent of the ouzo/absinthe effect in which the aniseed oils are frankly hydrophobic, but dissolve readily in alcohol, so by adding water slowly you create a micro-emulsion and it clouds, and tastes better.

It only takes a splash of water in a bowl of melted chocolate to seize it completely, and another two splashes to change it over into a glossy fluid oil-in-water emulsion (for ganache etc).

I don't know much about molecular structures in liquids but whisky and espresso both contain non-water-soluble substances dissolved in non-aqueous content (oil or alcohol) which is then mixed into water that contains other solutes too ... I would think the non-water-soluble molecules must be poking ends out into the water and altering the way the water molecules behave. If it's a concentrated (non-)solution ie most of the water molecules are already interacting with other solvents and solutes, then adding a twentieth part of the total volume of new pure water molecules sounds quite a lot in terms of changing the molecular structure of the liquid. Completely different from adding a twentieth part of the volume of water to an infused coffee which is already all about the water-solubles and contains dozens of times more solvent to solute.

If I understand other threads correctly, ristretto is not a simple solution but oil-soluble substances dissolved in minute oil droplets suspended in a continuous aqueous phase that is itself chockful of sugars, proteins, flavour-compounds and relatively large particles of suspended coffee bean.

So since blonde water doesn't impart much taste, you can just run 1 shot longer and 1 shorter to change the water ratio, thereby "opening" the espresso. This isn't TOO much different from experimenting with brew ratios to find the best one for coffee X. It is, however acknowledging that small changes in ratio can make a big difference. This leads me to want a volumetric dosing machine, but I hear they are inaccurate. A vario-w style espresso machine would be good for this (stopping the shot at weight X).

I'm no expert but I don't think just running a shot with half a gram more mass than the previous shot will open the flavors.

From what I'm understanding from this is that you add a couple drops of water (not just pulling the shot with more water) to get the results.