With a straight sided basket, I'd say no.

With a basket that's sloped in, maybe.

Most stock baskets are sloped in. The problem with them isn't so much the dose it's the tamp. Trying to tamp down an underdose with a sloped in sided stock basket is difficult. If you underdose a bit too much the tamper will get hung up and your tamp won't be even. That affects the extraction more than the dose level.

From what I remember of David Schomer's observations and theory from his book, 'Espresso Coffee: Professional Techniques', he advised to allow some head room for a fresh roast to bloom while extracting. Coffee will expand when soaked with water. If you've got an e61 theoretically there's even more time for the puck to expand before full pressure than a non preinfusing machine making underdosing more desireable.

With a Silvia I found underdosing a bit made for better tasting extractions. The guide at the time, I think was about a dime's width of space between the top of the puck and the showerscreen. With the stock Rancilio tapered sided baskets underdosing was very difficult. My extractions really improved after switching to straight sided baskets.

With my Vetrano I get my best tasting extractions with a straight sided double and using a reverse Stockfleth's move to distribute the dose. It ends with a bit of an underdose, that is with the tamping weight I use the tamper's top goes about 1-2mm below the rim of my straight sided basket.

The slight underdosing makes for better extractions, I find, with fresh beans atleast with my e61 HX Vetrano and a straight sided basket.

Marino Petracco in Espresso Coffee, 7.5.4, Illy & Vianni, eds wrote:During expansion, wet coffee grounds exert a pressure comparable to the wooden wedge once used to split marble ... On account of this behavior, an empty space is left above the ground coffee cake inside the extraction chamber. The actual expansion of the coffee cake varies by blend, roasting degree, and dose, and determines the minimum headspace (around 5mm to 6mm) needed to prevent over-compaction.

another_jim wrote:Instaurator's touch is Petracco's split marble.

As far as I know, that part of the Petracco comment has been largely debunked. From what I understand of the research done, there is pretty clear agreement that the expansion described doesn't occur until the brew pressure is released (ie post-extraction). Now.... that expansion can impact the expected lifespan of your dispersion screen....

I'm not sure if "debunked" is the right word for the legendary, unpublished, unreviewed glass PF video. Especially since the assertion that no expanspon takes place seems to imply that coffee particles do not expand when they absorb water; which, as far as I know, is false. But maybe I'm not up on the current evidence here.

I don't think anyone says the particles don't expand. But the particles expanding is not the same as the total dimensions of the puck expanding while under pressure....

Yep. But until we see it, we're just hypotetizing.

espressoed wrote:Akin to Randy's earlier observation about some machines with small baskets, I consistently get my best results when I dose to the extreme with nearly every coffee I use. Literally filling the basket so that when firmly tamped the coffee is little more than a millimeter from the rim.

Ed, I'm using a Krups too (for now) with a non-pressurized basket and find the higher dose preferable, BUT I often get side channeling with anything above 15 - 15.5 grams regardless of nutating, WDT, etc. At this dosing level, I probably have a few millimeters to the rim, so I can only assume your using higher doses. Are you doing anything special with your tamping?

Although there could be a difference in the machines, because I'm pretty sure mine is 51mm, I'm using Europiccola baskets.

John

Ed, Ed, Ed, thank you for posting. Just packed the heck out of the basket, nutating tamp, a nod to the gods to acknowledge no shot is perfect, and voila.... a really great pull. Not sure I would have ever tried that.

John