If 58 mm portafilters seem to be labeled as commercial grade/size, why do machines like the vivaldi or piston lever manual machines use much smaller diameter groups.

Does a 53mm hold the same amount of coffee as a 58mm.

Thanks, Will

I can put 18gr into the Vivaldi double baskets, no idea what a 58mm double will hold.

The word 'commercial size' is misleading since there are a couple of manufacturers (e.g. La Spaziale, Dalla Corte etc) not using the more ubiquitious 58 mm format for their 'commercial' machines. The difference in diameter being 5 (or 4) mm depending on who you ask.

As to the question why - the smaller diameters are e.g. said to be less prone to channeling than the 58mm format due to a deeper puck. The amount of coffee is independent of the diameter, you can get the same volume sized baskets for the smaller diameters too. The sizes 14g, 16g, 21g etc. are an approximation anyway as you can up or downdose any of these.

There are a couple of threads out there discussing this subject (particularly since the Vivaldi arrived), I suggest you take a look at these and do a search.

expobar-brewtus-ii-vs-la-spaziale-s1-t1020.html
how-many-grams-does-your-portafilter-basket-hold-t3765.html
changes-in-dosing-and-leveling-technique-from-58mm-to-53mm-basket-t4992.html

There are other formats out there as well, check this one out:

http://coffeegeek.com/forums/espresso/machines/10421

I'm reviving an old post but I just want to say that I've been very impressed with the smaller 53mm basket size on my new Vivaldi.

At first I was turned off by the smaller size (a "man thing" I'm told) but after using it for a week now, I've changed my mind.

The higher sides seem to reduce channeling quite a bit. Another benefit of the smaller diameter is the edges are less affected by tamper tilting. Finally, the basket diameter seems to be much more accurate than the 58mm baskets. (Half the 58mm baskets I owned left 2mm gaps around the edges).

The only down-side is the pucks are harder to knock out of the basket (further evidence of a good side seal?).

I'm using an Espro 53mm convex tamper and the fit is just perfect.

In Italy, 90% of all shots are straight single espressos pulled from a single basket. For these, the group diameter is irrelevant, since the single basket's puck area has an effective diameter of around 49mm to 51mm. Most Italian machines are primarily designed for this market, and the double basket and optimizing its behavior is not high on the engineering priorities.

That being said, I've heard some engineers (obviously working with 58mm groups) say that for doubles, the aspect ratio of a 58mm puck is optimal, while a 53mm is too narrow and deep.

My experiments of measuring the extraction at various levels of the puck show that the upper levels are more extracted than the lower levels. So the deeper the puck, the more uneven the extraction top to bottom. Given you want to extract between 20% to 25%, it seems there is a maximum proper puck depth, and going deeper will under extract the bottom and over extract the top. However, I don't know what that depth is or how other variables affect it.

To Paraphrase Rabbit:

1. An idea: One would expect the finer grinds to find their way to the bottom of the basket.
2. Thus, one would want the upper levels to extract slightly more than the lower,
3. So deeper narrower baskets are better, unless the grinder is perfect,
4. Which they aren't,
5. Which is one reason why its so easy to get good extractions with the old 43, 45 mm Italian home levers

One thing I'd like to mention is that deeper basket makes it more difficult to tamp the coffee evenly. The deeper layers of the puck can be less pressurized than at the surface. Actually i am not sure if it really matters. I had a chance to operate new Astoria machine (53 mm) and it worked (and also frothed) perfectly.

There definitely seems to be a taste difference between the 58mm (like the E-61 Anita I used) and my current 53mm (LaSpaziale Vivaldi). Which one you prefer depends a lot on your taste and what coffee you are using.

I do miss my old ridgeless basket (not available on the Vivaldi).

It would be interesting to hear a description of the taste difference by one of our "tasting gurus" in a blind back-to-back test.

Advantages of the smaller diameter basket:
1. With a reasonably deep tamper base, it is nearly impossible to do a tamp that isn't level.
2. Shots are more predictable with a higher percentage of "good" to "very good" shots.

However, in another thread, I wrote about being startled this weekend by the number of flavors that appeared in my cup from a shot made at a restaurant with a customized La Marzocco and well-trained staff (BarBambino in S.F.). This is what some call "clarity." They were using the same coffee I was using that week at home (Ecco Reserve).

So, I've ordered a bottomless portafilter and am going to tweak my technique to see what happens on my Dalla Corte (54mm).

Marshall wrote:Advantages of the smaller diameter basket:
1. With a reasonably deep tamper base, it is nearly impossible to do a tamp that isn't level.
2. Shots are more predictable with a higher percentage of "good" to "very good" shots.

With one notable exception , I tend to agree with Marshall most of the time. But I'm going to take issue with this post.

First, let me assure you that it is indeed possible to to perform a non-level tamp in a smaller diameter basket (in my case, 53mm Spaziale double basket, Bumper tamp with nice thick base). Maybe I'm just talented.

Second, the jury is still out on optimal basket size and shape. Answering this question will require a careful study performed on two otherwise-identical machines, one with a 58mm grouphead and the other with a smaller (53-54mm?) grouphead. I have not noticed any increase in predictability with a smaller diameter basket, but there are many other factors at play in my system (comparing 58mm HX to 53mm DB to 51mm manual lever).

My WAG: the 58mm grouphead standard has evolved for a reason, just like the near-universal recommendation of 9 bars brew pressure in pump machines. It's probably near optimal for the majority of current espresso machine designs.