'Nutating tamp'. Used to be popular. I practice it to try seal puck edges with a 58mm tamper. I don't see any gaps around the edges in a pulled puck so I keep doing it. It's a habit that works for me.

Nutation: how to do it right

Nutation . . . . As in--- "I used to be a nutator, but I stopped nutating when I couldn't remember why. It's hard to ignore any hint from Jim (that's why I bought an Isomac Tea back in . . whenever), but even his suggestions must occasionally expire. So I thought I'd ask for an update.

I stopped using nutation; it was inconsistent for me and my puck prep. After nutating, using several different levelers, etc., over the years it seems, after using the collective needle approach for the past 6-months or so, the needle swirl Lance described works the best for me. Per Jim: YMMV

Martin wrote:Jim. ... you rotate the tamper to emphasize the outer edge of the puck ... Did you abandon that?

Nope, I nutate and tamp lightly. The puck does have to be fairly level and clump free.

But how level and clump free? The problem with cylindrical baskets is that they amplify irregularities in the puck, rather than snub them. So the puck prep in cylindrical baskets has to be fastidious; since any slip will ruin the shot. The question is what does all this added difficulty gain you. Tapered baskets snub and repair irregularities in the puck, and make life much easier.

This means that people using untapered, cylindrical baskets need to be very convinced indeed that these produce better shots. Where's the evidence for this conviction?

Ah, my life is guided by that contradiction: A constant search for evidence to support my convictions.

Martin wrote: but even his suggestions must occasionally expire. So I thought I'd ask for an update.

I was curious as well. Nutatating tamp or what ever you want to call it works for me. Good grinder, good puck prep, capable machine gets me good extractions with what I've got. There is no expiry on what works.

another_jim wrote:This means that people using untapered, cylindrical baskets need to be very convinced indeed that these produce better shots. Where's the evidence for this conviction?

I don't think the newest theory based basket, portafilter, tool, etc. costing hundreds of dollars would get me much better tasting extractions than I already get. There was a discussion about that some time ago and one of the positions was that the average sense of taste isn't acute enough to detect subtle changes in extraction. I tend to agree.

Thanks, Jim, for the Strega review. It is a really good machine.

OK...not to derail this nutation thread...but I do appreciate the point that puck prep is foundational. Still, I would love to hear more from folks using some sort of flow control and if it's effected their consistency (including, of course, signs of channeling).

at any time u start having spritz, reducing flow isnt going to help. its already a weak path for water to follow. it sprits less strongly instead. i tried.

personally i think getting proper puck to screen gap is more important than basket size. use the coin method.
get this level and right, then u'll have well distributed water from the screen to the puck, minor spritzing or split flow would matter less.

i also found my ims 58mm notoriously prone for spritzing than others. i have bdb singles, doubles, vst15, vst18, decent18, and uses them all. they fit slightly different doses due to both shape and size, but i mostly prefer the 15. the 54mm ims was very good and well behaved tho.

I have, on occasion, been able to use flow control to improve the likelihood of a picture-perfect looking shot. This is due to (I think) my ability to impact how the puck is pre-infused, which can result in a more consistently saturated puck, which reduces the likelihood of a channel.

That said, on medium-dark and beyond, I've not seen any benefit to flow control in terms of picture-perfect flow. Flow control is more useful for medium and light. And I think it varies by coffee. And I think it's incredibly hard to control and repeat over and over. (Unless you only drink a handful of coffees - I go through 50-100 coffees/year)

Separately, but related, once a puck is saturated and starts to drip/flow, I've seen no benefit to using flow control to "fix channels and spritzes". In my experience, at that point you've made your bed and now you need to accept your fate.

In my experience the use of a flow control to mitigate POTENTIAL channels is mainly about the phase in which you use it.

If you use a pressure hold around 2-3bar/zero flow stage at the beginning of the shot then the puck does seem to have an opportunity to saturate and swell which can ameliorate potential weak spots in the bed BEFORE they become channels.

Once you are at full pressure and the water is flowing through a channel there is most likely little to be done except minimize the mess.