I just started to use VST 20g basket, I found two holes in the center of the puck, any cause?

Thanks

Reading a puck like that post shot is nearly like reading tea leaves. One can look for dry spots in the puck or accumulation of dark spots on the bottom of a portafilter. Since the machine releases pressure through the discharge the puck typically expands rapidly which can cause marks that weren't there during extraction.

It is best to watch the bottom of the portafilter (bottomless) for signs of channeling and further confirm by tasting.

The puck looks dry. You can knock it out on something flat like a plastic lid to check the bottom. I knock mine out on a yogurt lid to check the bottom. Saves wear on the knock box as well.

There's what looks like an indent of a portafilter gasket around the perimeter of your puck. You might not have enough headspace and getting a showerscreen tamp. It limits the puck's blooming. Try decreasing the dose to increase headspace.

In terms of dose, since my vst is 20g, i tamp 20g , I will try to lower dose a bit , or tamp harder to give a bit more headroom?
Thanks for advise .

Search on "puckology" to read other prior discussions.

FWIW, I agree with the other posters that (a) it looks like a dispersion screen impression, (b) looking for evidence of channeling with a bottomless portafilter offers more insight potential. As for tamping harder: That won't change the puck-to-screen clearance; besides, the water pressurization compresses the puck much, much more than any barista can with a tamper.

By the way, how does the espresso taste? For me, that's really what matters.

"20 g" on a basket (of any make) is a suggestion that is probably outdated today. When VST baskets were first introduced, it was reasonably common to fill the basket from a grinder's doser and sweep off the excess with a finger. Dosing by volume was consistent enough for the coffees and cafes of the day, and many still today.

Depending on your coffee, grind, and headspace, you might get 10-20% more or less mass in the basket than the number on the side. One notable "14" has the volume of a typical "18". Pick a basket that holds the dose you want and gives you sufficient headspace.

Well, it looks like I have to lower dose a bit, I always use finger to wipe off the excessive dose till I got this vst 20g, I started to measure and weight my shot every time. Taste wise, I found by measuring my shot in 20g gives a bit sour, and cleaner taste vs before I use 18g stock basket which gives full body and no sour hint. I actually prefer my previous taste better vs the new VST basket, which way I can bring less sour. More body to my espresso by using VST?
Any suggestion?

Don't use a VST or high-flow basket.

They aren't "better" than current baskets for all people and their coffee, gear, skills, and tastes.

Detour101 wrote:In terms of dose, since my vst is 20g, i tamp 20g , I will try to lower dose a bit , or tamp harder to give a bit more headroom?
Thanks for advise .

The real capacity of any basket depends on how far into the portafilter the dispersion screen extends and coffee density...use the 20g as a guide and be prepared to use less/more

Hello, I use ent, from the bottom of the portafilter it still look like I have some uneven extraction, when knocked out the puck it doesn't appear as a one pieces of cake, it's cracked into pieces, any idea to fix ?