Would you prefer volumetric or timed dosing?

[hbuchtel]

I'm just curious, if you were given a choice, would you prefer to have volumetric dosing or timed dosing on your espresso machine?

I don't yet have a preference, but I'd like to hear everybody's thoughts on why one would be preferable to another.

Thanks, Henry

[iZappa]

I would prefer timed dosing. Full control over the brewing process. Also timed dosing forces one to pay attention to what you are doing. Volumetric dosing is of course handy when brewing many espresso's in a row. But still I tend to use the manual control. My preferences only.

[zin1953]

. . . would you prefer to have volumetric dosing or timed dosing on your espresso machine?

Henry, just to be clear, are you juxtaposing volumetric dosing (with automatic shut-off) to having a timer that you watch, or some sort of timing device that would also provide some sort of automatic shut-off?

Cheers,
Jason

[mrgnomer]

Depends on the design of the machine, I guess. Volumetric dosing, I believe, uses flowmeters to regulate adjustable brew water volumes. Preinfusion on the same machine, if offered, would be controlled by solenoids. It's an electric method of controlling brew pressure profiles and volume.

On the other hand a lever actuated e61 group, if that's what you mean by timed dosing, is a physical control of pressure profile and water volume. No solenoids or flowmeters required. Shot timing is controlled by the operator via the lever.

If there are machines that time the extraction rather than control it by brew water volume I don't know about them. Either way if the puck was badly prepared it wouldn't matter to the extraction, I would think.

From what I've read and from my experience with the true e61 lever acutuated group I would prefer the e61 lever. A design that doesn't rely on electronic feedback appears to be more desirable for full control and dependability.

In a commercial setting, however, where I'd have to bang off shots fast, volumetric dosing would be much faster and more convenient, I'd say. Lock in, push a button and while the shot is extracting start building another.

[zin1953]

I suppose I should have expressed my opinion . . .

Either way (in terms of using a timer [see above]), I would prefer volumetric dosing. That said, take it with a grain of salt -- it's what I have now.

Most of the time -- say 80%-90% -- I am stopping the espresso "pull" prior to the time/volume that the volumetric dosing flowmeter would shut it off. But not having three hands, it is nice to know I'm not going to lose it completely if, say, I'm still steaming milk when the shot hits 1.75-2.0 oz . . . or if the phone rings, and I don't feel like hitting "stop" when my shot has just started . . . or . . . or . . . or . . . .

If you're just talking about a small timer attached to, say the front of the machine, it's just one more thing I have to watch. In the morning, I typically make one latté (wife) and one cappuccino (me), and I'm steaming the milk as I'm pulling a shot. Sure I keep one eye on the milk and one eye on the shot, but I'll confess most of my attention is on the milk. And most of the shots that get cut-off automatically by the flowmeter occur when I'm still steaming the milk. If I have to glance at the timer, too . . . (shudder).

It's just easier -- for me -- to "rely" on the volumetric dosing flowmeter as a sort of "backup system."

Cheers,
Jason

[hbuchtel]

Sorry, I wasn't very clear about what I meant by 'timed' dosing-

Basically it is the same as volumetric dosing, except that instead of turning off when a set volume is met, it turns off after a set amount of time.

With volumetric dosing you set the volume (1.5 oz, for example), then adjust your dose and grind so that it automatically shuts off at about the same point that you would have shut if off manually.

Timed dosing should be the same- you set a certain time (33 seconds, for example), then adjust dose and grind so it shuts off at approx the right time.

This is assuming you can consistently build the same puck, of course.

I had always assumed that volumetric dosing was 'superior' in some way... just because all semi-autos seem to have it... but now I'm thinking it has more to do with commercial needs (ie same amount in cup each time) and simply tradition then anything else.

I can appreciate that some people like to shut off each shot manually, but right now I'm really enjoying working with the timed dosing that I have on my pump machine. I've settled on a 12g dose and 33 seconds, and it is a fun challenge to consistently get to my chosen blonding point in the set time. (to pre-empt the "Marshal Response," I should mention that I chose the dose, time, and blonding point 'cause it tastes good )

Regards, Henry

[AndyS]

I've settled on a 12g dose and 33 seconds, and it is a fun challenge to consistently get to my chosen blonding point in the set time.

For quite some time, Jim Schulman has mostly advocated that we shut the shot off when a given color is reached. That's a little more complicated that using time or volume. But given modern control technology, inexpensive optical sensors and a little fooling around, shot termination based on blonding point could be easily automated.

[cafeIKE]

Choose :
A - Time
B - Volume
C - Color
D - A, B and C
E - None of the above

D, every time.

[Marshall]

... (to pre-empt the "Marshal Response," I should mention that I chose the dose, time, and blonding point 'cause it tastes good )

Regards, Henry

Great, now I'm officially a cliche (or more likely, just tiresome). Anyway, even though my grinder shuts off with a timer, I often have to pulse a half second or so, because the beans haven't flowed steadily through. So, I think there always has to be means for some human intervention.

[malachi]

Neither.

[hbuchtel]

D, every time.

Neither.

Thanks guys...

shot termination based on blonding point could be easily automated.

That would be pretty cool... ummm... it would get dirty? And it would depend on the ambient lighting? (as does stopping manually by color) How much do you think a production model would cost? An advantage of timed dosing is that it would add a couple of bucks to the cost of a machine, if that. The flowmeter and d-pad on volumetric dosing machines cost a lot...

I was thinking that the habit of relying on volumetric dosing might have its origins in the fact that commercial pump machines evolved from lever machines, which effectively have volumetric dosing.

Henry

[cafeIKE]

But given modern control technology, inexpensive optical sensors and a little fooling around, shot termination based on blonding point could be easily automated.

Me thinks not, at least in any useful commercial way.
One maybe able to tune a sensor array after a decent number of learning shots, but change the roast, blend, temperature and all is naught.

Dynamic TDS may have some possibilities...

...in the mean time about 60ml in about 30 sec from about 15g around 92C stopped just before the stream goes watery will suffice.

[Paul]

a mate of mine has some experience servicing timer machines back in their heyday (late 70s-early 80s). If I recall correctly, his main beef with them is that they weren't a particularly good solution in a working environment. Obviously the grind and tamp influences extraction rate. In a timed system variation in either of these results in different shot volumes.

I would guess that the introduction of timers was an attempt to economically effect automation using a regular group. You might have seen funky mechanical dosing groups that faema and others used to produce. I guess that due to their complexity these would have been much more expensive than say a e61 design.

FWIW, I think one of the last mfrs to employ a timer gr in their lineup would have been BOEMA of Australia.

Anyways . . . I haven't answered you question Henry. I really don't know. My current lineup ranges from a linea av to various 50s leva machines. I just love em all

[AndyS]

Me thinks not, at least in any useful commercial way.

Of course, as Chris Tacy implies,volumetric dosing isn't useful commercially either -- except in the sense that it makes it easier for second-rate baristas to pull third-rate shots.

The idea for a machine that ends the shot based on color wasn't a serious commercial suggestion, just a musing about what the possibilities are for geeks that find this kind of experimentation fun....

[hbuchtel]

I'm puzzled by the attitude that having a fixed dose is somehow going to produce worse coffee... or that it isn't '3rd-wave' enough, or something like that...

Most of you accept that you don't have live control over brew pressure, right? You set the OPV and away you go... but any manual lever user will tell you that the pressure can vary a lot between shots, and that what you do with the lever shows up right away in the cup.

I don't want to come across like I'm saying that levers are superior to machines with OPVs... they just provide another variable (well, there is pre-infusion as well!) for the user to play with.

In my pump set-up, the coffee dose, tamp, temperature, pressure, and time are all 'set.' What I play with is the grind (and the age of the grind ). However, there are still more variables that I have not identified, as the espresso weight and the... ok, hang in there... the .. t-t-tt-taste can vary a lot even with the same grind.

Henry

[hbuchtel]

a mate of mine has some experience servicing timer machines back in their heyday (late 70s-early 80s).

Hey Paul, thanks for posting this... I didn't know that timed dosing used to be popular!

I'm with you on the "gotta love 'em all" sentiment

Henry

[Paul]

with regards to why barista's prefer semiautos I would guess it is the added element of control. I wonder though, how would one get on in a very busy cafe without dosing?

[zin1953]

Of course, as Chris Tacy implies,volumetric dosing isn't useful commercially either -- except in the sense that it makes it easier for second-rate baristas to pull third-rate shots.

with regards to why barista's prefer semiautos I would guess it is the added element of control. I wonder though, how would one get on in a very busy cafe without dosing?

Speaking -- just for a brief moment -- of a home environment, a semi- AND an auto offer the same degree of control as long as you watch your shot and stop it manually, if necessary. (As I said above, I use the "automatic" feature is a "backup" in case of distractions/interruptions; most of the time, I stop the shot myself.)

Back to a commercial environment . . . I know several cafés and/or individual "barristas" (and I use that term loosely) who would benefit from using volumetric dosing . . . they have no idea what a ristretto/"short pull" is! Even some who do occasionally let the shot run long due to the specific environment/pace of the shop at the time . . . More than once, I've asked someone to re-make my ristretto, as it isn't very "restrained." AND more than once I've just had my coffee and left, not wanting to explain to the overwhelmed employee what is wrong with 10-12 people standing in line . . . (and yes, Andy -- in that case, it IS a second-rate barista pulling a third-rate shot, but on a semi -- with a fourth-rate customer just accepting it).

As I've said before, were I to ever open a "serious" café, I'd opt for automatic machines and train my employees to watch the shot and stop it manually (as they would have to do if using a semi-auto).

Cheers,
Jason

[gscace]

Great, now I'm officially a cliche (or more likely, just tiresome). Anyway, even though my grinder shuts off with a timer, I often have to pulse a half second or so, because the beans haven't flowed steadily through. So, I think there always has to be means for some human intervention.

You're also a verb. Marshall your resources!!

-Greg

[gscace]

I'm puzzled by the attitude that having a fixed dose is somehow going to produce worse coffee... or that it isn't '3rd-wave' enough, or something like that...

Most of you accept that you don't have live control over brew pressure, right? You set the OPV and away you go... but any manual lever user will tell you that the pressure can vary a lot between shots, and that what you do with the lever shows up right away in the cup.

I don't want to come across like I'm saying that levers are superior to machines with OPVs... they just provide another variable (well, there is pre-infusion as well!) for the user to play with.

In my pump set-up, the coffee dose, tamp, temperature, pressure, and time are all 'set.' What I play with is the grind (and the age of the grind ). However, there are still more variables that I have not identified, as the espresso weight and the... ok, hang in there... the .. t-t-tt-taste can vary a lot even with the same grind.

Henry

I don't see why volumetric or timed dosing won't work just fine once all the variables are correctly controlled. The problem is that we only can control temperature, pressure, and grind fineness distribution reproducibly. We don't control dosing, distribution, tamping worth a rats ass. Automated systems with proper feedback controls could work just fine, provided that a proper feedback signal is used. It's pretty hard to automate taste buds right now, but you know it's coming.

The problem right now is that a really good barista can blow away automated machines. That is a problem because it means that a ton of work and effort must be expended to achieve the expertise level required and so lots of crap coffee gets made. It's not a problem if you think coffee should be the product of artists.

-Greg