Dosing as a variable ?

[webhead]

Hi all,

After a lot of tweaking on the part of my machine I got it in "the zone" pressure wise and temperature wise (after a small flush). So now it's up to my skills to do the rest.

I set the grinder, use my scoop to dose the amount of coffee, pretamp it with way too convex plastic-grinder attached thingy, level it some more, tamp, twist, tap, tamp twist.

Works nicely: I usually need 1 calibration shot to see if the grinder was set correctly.

Now for the tweaking:
It still happens that the shot pulls too fast (21seconds, a bit too weak imo) and one grinder notch further I'm doing 35secs/shot and although the crema is darker, more punch in the shot etc but it is a tad over extracted and a bit bitter.
Sooooo... I thought about messing with my tamping but that just seems awkward. I got a reasonable feel for a consistent and even (thank you naked filter) tamp. Doing the 35 seconds fine grind and tamping lighter just feels off the mark here.

What about just slightly increasing the dose on the 21sec grind setting? Instead of a leveled scoop maybe a bit more ? I'm not going to go scale-dose crazy just yet...

[Randy G.]

While changes is dosing may change pull times a bit it will also affect taste. If it is the best possible taste you are attempting to achieve then you need a stepless grinder. I went from a Rocky to a Mazzer and will never go back to a stepped grinder for espresso.

[Elbasso]

Sooooo... I thought about messing with my tamping but that just seems awkward.

To my experience it is also useless. As stated "The professional barista's handbook": 9 bar pressure = 130.5 psi. Coffee in 58-mm basket has a surface area of 4.09 square inch. The pressure exerted by the pump is therefore 130.5 x 4.09 = 533.7 lb.
This exceeds the manual tamp by a mile. Because of this the coffee will pour just as fast with a light tamp as with a tamp from hell.

As Randy said, stepless is the only way.

[webhead]

The grinder works by a large screw-in burr above a rotating one. Screwing it down shortens the distance. The lower side of the screw-in burr has notched and thus "clicks" in lock.
I'm sure I can convert it to notchless just by providing another way of locking the burr. I'm not ready to start drilling my grinder... yet.

In what way would adding 1g of coffee to a double change the taste and extraction time?
Suppose the extra gram adds some resistance and make the 21" shot a 25" one. I think it's feasible. This would yield a more complete extraction, more punch etc but not like the 35" over extracted one.
Maybe that it will alter taste but it can't result in a bitter overextracted cup since it's never overextracted in the first place.

Speaking of that pressure: I figured the whole tamping hard/harder/hardest thing was overrated. Imo the first reason for tamping should be to build a solid puck to withstand the pour without cracking or channeling.

[RapidCoffee]

In what way would adding 1g of coffee to a double change the taste and extraction time?
Suppose the extra gram adds some resistance and make the 21" shot a 25" one... This would yield a more complete extraction, more punch etc but not like the 35" over extracted one.

Varying dose (and brew ratio) is certainly reasonable. There is always a range of acceptable doses for a given bean/grind/basket/machine, although the sweet spot may be wider for some combinations than others.

Those are really large steps on the Santos grinder (21sec -> 35sec ). Another thing to try (although perhaps slightly annoying in practice): grind half your dose at the finer setting and the other half at the coarser setting. That should get your pull into the 25-30 second ballpark.

[AndyS]

While changes is dosing may change pull times a bit it will also affect taste.

OK, but changing grind fineness also changes taste, no?

If it is the best possible taste you are attempting to achieve then you need a stepless grinder. I went from a Rocky to a Mazzer and will never go back to a stepped grinder for espresso.

That's the conventional wisdom, espoused by Schomer and thousands after him. But nowadays, people are becoming more open-minded. Maybe stepless grinders aren't essential after all. Keeping the grind reasonably constant and varying dose has many advantages.

[malachi]

You can absolutely "fudge" extraction using dose.
It will, of course, alter flavour profile.

I'd echo others here and suggest that you either go to a stepless grinder or at least a grinder with more steps.
But in the meantime, I'd definitely encourage you to experiment with small changes to dose and see how it affects the results in the cup. And even if you do change grinders - I'd still suggest experimenting with tuning extraction by altering dose. It's a fantastic learning experience.

[roblumba]

I say just do it and tell us what you think. But if you up-dose it also helps to go a little higher temp because more coffee means that it needs a little more heat to heat it up and so the temperature of the brew water hitting that puck needs to be a little hotter. Like just 1-2F.

Sometimes when a coffee is acting like it wants to be more fine a grind than I'm comfortable with, I'll up the dose instead of grinding finer. But like I said, the temperature may need to go up a bit too. Or not. If you can't find the right flavor your looking for and don't want to get a new grinder, find some beans that work better. That's what I ended up doing with my older ECM Giotto. And even now with my GS3 I bought some local beans on a whim that were crap. All the variations I could think of all amounted to horrible espresso. The beans were too oily and I think they just went bad fast, so I tossed them and went back to Barefoot and bought 3 bags of Boss. Problem solved.

[malachi]

Be cautious on the "increase temp as you increase dose" theory.
With a fair number of coffees, this results in ashy shots. In fact, in a bunch of cases in my experience, I've had to decrease temp in order to maintain flavour profile with increased dose.

[roblumba]

Be cautious on the "increase temp as you increase dose" theory.
With a fair number of coffees, this results in ashy shots. In fact, in a bunch of cases in my experience, I've had to decrease temp in order to maintain flavour profile with increased dose.

Thanks for checking my theory. I'll be looking for that ashy taste. One of the reasons I mentioned higher temp for higher dose is because I thought the same temp at a lower dose would really bring out some bad flavors particularly towards the end of the extraction when it starts fading from the darker color. My thinking was that a lower temperature would help tame those bad flavors a bit towards the end of the extraction. So are you saying that a higher temperature at lower doses would actually help? Is it helping the extraction over all or is it bringing out more flavor in the beginning of the extraction?

I would love to hear if you have some thoughts on how this temperature vs. dose relationship works in relation to the stages of extraction because there is a marked difference between extraction flavors at the beginning of extraction vs. the end and the dose play a big part because larger dose mean that there's going to be more oils extracted over that same amount of time, into the same volume of espresso.

[cafeIKE]

Be cautious on the "increase temp as you increase dose" theory.
With a fair number of coffees, this results in ashy shots. In fact, in a bunch of cases in my experience, I've had to decrease temp in order to maintain flavour profile with increased dose.

IMHO - the habit of assuming that one's experience is generalizable or in any way represents "reality" is the primary cause for much of the disinformation on this site.

Couldn't resist

I don't think a hard and fast rule is possible. Some machines droop and others rise at the end of a shot.

On my machine that droops, I pull current coffee singles hotter than doubles. On a similar machine that rises, no change.

[malachi]

I would love to hear if you have some thoughts on how this temperature vs. dose relationship works in relation to the stages of extraction because there is a marked difference between extraction flavors at the beginning of extraction vs. the end and the dose play a big part because larger dose mean that there's going to be more oils extracted over that same amount of time, into the same volume of espresso.

Sadly, I don't think there is any way to generalize the relationship.
Just as there are coffees that some people like the taste of when up-dosed and that others like down-dosed and just as their are other coffees that work out differently, I think that there is no way to make a claim to some sort of "golden rule" for a relationship between temp and dose.

I like the Stumptown Hairbender heavily up-dosed and pulled at around 197.5F. Others don't.
I like the Ecco Caffe Reserve slightly down-dosed and pulled at around 200.5F. Others don't.
I like the Ritual Sweet Tooth slightly up-dosed and pulled at around 201F. Others don't.
I see no real pattern here.

You just have to experiment and find out what parameters you like for each coffee.
I find it fun!

[Gugies1]

Hi All,
Dosing as a variable? From my experience it is a key variable. I have been spending a bit of time working on the mechanics of brewing drip coffee which have changed how i look at espresso. in your average cafe or home setting pump pressure and water temperature are not being changed on a shot to shot basis. the barista is effectively controlling two variables, grind size (the total surface area in contact with water) and dose amount (how much coffee is given). so i am in essence saying you are controlling both the strength % which is the amount of TDS in the final product and also the extraction % which is the amount of solubilities removed from the coffee during extraction. both of which will affect the final flavor of the espresso. the big question that lurks in my head would be if this means that individual coffee's have optimal yields of strength and extraction? if so is it based on processing, origin, variety, roast, something else? if so is it ever possible to have a perfectly reproducible bean where nothing deviates between all of those variables over time/roast batch/age/ect.?

[webhead]

True true.
But as the dose is varied and so is the grind and I'm sure the sweet spot varies with the beans as well, why would the extraction time remain constant ? Ok, in general between 23 and 30 is "accepted" and I have noticed what under and overextraction does to a cup. However, couldn't the time vary with the beans as well ?

It just occurred to me while I was experimenting for that 25 seconds shot (give or take 2) that I might be chasing the wrong thing here.

[Gugies1]

for sure i would say that time is a variable at this point but i wonder if it is truly a variable or being used as a control to account for other variables that may be far to complex to practically control. i have definitely given up the "acceptable" time window recently after many repeated 42 second great shots from a blend made to be pulled at around that time. i guess in the end after all of the high level theories it comes down to if it tastes good.

[roblumba]

I like the Stumptown Hairbender heavily up-dosed and pulled at around 197.5F. Others don't.
I like the Ecco Caffe Reserve slightly down-dosed and pulled at around 200.5F. Others don't.
I like the Ritual Sweet Tooth slightly up-dosed and pulled at around 201F. Others don't.
I see no real pattern here.

You just have to experiment and find out what parameters you like for each coffee.
I find it fun!

I see a pattern. You do things differently than other people

I see your point but at the same time there is a flavor profile that the roaster aimed for. Although you can go all over the map and find all sorts of flavors, there is a recipe for the brewing that creates the flavors that were intended to be communicated. I think there is great value in that. It's not exactly a "golden rule", but in a very practical way, it's dependable, work well, and is very tasty.

[cafeIKE]

Most of us don't have space for 50 machines. For example, a local roaster had a LM 3 group and a Rancilio lever. A coffee, dosed on a Swift, is great, but very different, on the two machines. Which is the right taste?

If I try the LM numbers at home, it's not very pretty. By adjusting parameters, I get a great shot, not the same as either of the roaster's machines, but a great shot, none the less.

[roblumba]

That certainly makes communication difficult. I guess each person needs to understand how their particular machine translates the roaster's parameters. HB forums make it easier for a particular group of users with similar machine and grinder characteristics to share their experience with a particular coffee.

[malachi]

I see your point but at the same time there is a flavor profile that the roaster aimed for. Although you can go all over the map and find all sorts of flavors, there is a recipe for the brewing that creates the flavors that were intended to be communicated. I think there is great value in that. It's not exactly a "golden rule", but in a very practical way, it's dependable, work well, and is very tasty.

Call me a post-structuralist, by my interest in "intended flavour profile" is purely academic.
I'm far more interested in "desirable" flavour profile.

[webhead]

So if I get it correctly, aside from the obvious errors dosing and distributions wise, channeling, a much too fast or stalled shot everything is open for personal preference to decide.
That certainly shines a different light on some of the "rocket science" topics.