Dosing/tamping has already been widely debated here but...

When I dose so that the top of the puck hardly touches the shower screen screw before brewing, the puck is too shallow because my 58.0mm tamper gets stuck by the rounded bottom of the basket (I'm using a stock double basket). In this case, the basket holds 12g/12.5g of coffee and I have no idea how hard I really tamp.

If I put a bit more coffee, the tamper is no longer stuck but I can clearly see the shape of the screw inside the puck before brewing. Besides, the coffee expands while brewing and gets stuck by the shower screen.
My feeling is that the problem is simple (my tamper is too wide) but I can't believe I'm the only one to use a 58mm flat tamper with silvia and to face this problem.

I found out that Rancilio is making 2 different double baskets: 12g and 14g.
So, what size of tamper do you folks use with this basket? Do you use this basket?
Thanks!

Chris

Er, how's the coffee?

Well, I get acceptable results in the cup in case #2 most of the time (when I manage to buy fresh beans...), but I set the bar for myself higher than this, "acceptable most of the time" is not enough and that's why I'm doing some trials.
So yesterday, I tried underdosing a bit. I got poor results but as my "new" beans behave the same as my older beans, it's very likely that they're stale as well and I guess it's the reason for these bad results.
But that's not my point, as far as I understand, I would face the same dosing/tamping issue with fresh beans. Right?

I have a stock Rancilio double basket I mistakenly ordered to try a lower dose basket. Even with a 14g dose, my 58mm tamper binds on the sides before I can get any reasonable pressure on the coffee.

miam-miam wrote:But that's not my point, as far as I understand, I would face the same dosing/tamping issue with fresh beans. Right?

Of course you should be using good quality, freshly roasted coffee beans. But in this case, the solution is obvious: get a different basket! That should eliminate any difficulty with tamper fit.

Personally, I'm a big fan of ridgeless double baskets.

RapidCoffee wrote:Of course you should be using good quality, freshly roasted coffee beans. But in this case, the solution is obvious: get a different basket! That should eliminate any difficulty with tamper fit.

Personally, I'm a big fan of ridgeless double baskets.

I second this. I purchased a synesso 18g ridgeless double and use a convex 58mm tamper. Once mod I also did is removed the screen bolt and modified it to accept a flush mount bolt. I can now dose up to 17-18g without touching the screen.

miam-miam wrote:When I dose so that the top of the puck hardly touches the shower screen screw before brewing, the puck is too shallow because my 58.0mm tamper gets stuck by the rounded bottom of the basket (I'm using a stock double basket). In this case, the basket holds 12g/12.5g of coffee and I have no idea how hard I really tamp.

This is where you go wrong. Compared to other machines, shower screen screw of all rancilio machines much more protruding. take a look at these --> rancilio silvia shower screen, marzocco linea, smooth e-61 shower screen, nuova simonelli oscar shower screen (edit: dan warned me about ns oscar's shower screen, it's a pod one but that's the only picture I could find for oscar --showing screw-- anyway keep in mind it's for you to see the screw part not the whole group head edit2: thanks to dan, changed ns oscar link)

So you're definetely downdosing. Grind one or two steps coarser and use more coffee, don't worry about the screen screw. btw check your double basket's code (it's carved on your basket) the code for 14gr double basket 40.100.010, and 7gr single basket 40.100.001 All rancilio machines (silvia, epoca, classe 6, 8, 10) use exact same baskets.

try dosing and tamping like this





For your tamping, if you have a bathroom scale grab your tamper and push until you see 30lb/15kg do this several times so that you get used to it. That will teach you how to control your tamping pressure and from there you can tamp less or more.

edit: forgot to add this --> as far as I know there's not an official 12gr rancilio basket. Those 2 above with codes are the only ones (and there's another triple basket coded 40.100.096 but it's not in rancilio spare parts catalogue yet. besides you'll need triple portafilter with triple basket)

I think I don't get your point with this screw: I agree it's in the way and it might disrupt the flow but what's its impact on the dose?
In order to prevent the coffee from touching the screen while brewing, I noticed the coffee level after tamping should be such that it hardly touches this screw, ie the level is just under the bottom of the ridge.
In my case #2 (ie what I usually do), I get the same level as you.

I saw the 12/14g baskets here http://www.pasmarose.de/catalog/index.p ... 119_81_207 but maybe it's a typo?

As mentioned by rapidcoffee, the natural solution is obviously to find a deeper and/or more cylindrical basket, but I'm just surprised not to find similar experiences on HB. Should I conclude I'm focusing on a fake problem? (I mean if puck expansion is stopped by the screen)

miam-miam wrote:Should I conclude I'm focusing on a fake problem? (I mean if puck expansion is stopped by the screen)

If your tamper binds in the Rancilio basket, that limits dosing (and tamping) options. So yes, I think it's a problem. An inexpensive, simple solution was offered above, and additional verbiage is really unnecessary.

Get a different basket. You won't regret it.

miam-miam wrote:I think I don't get your point with this screw: I agree it's in the way and it might disrupt the flow but what's its impact on the dose?

Which screw do you have? Some came with a round slotted screw, some with a slotted hex-head (bolt?) and others have had their round head screw replaced by a countersunk Phillips, or Allen Flat-head screws.

If you have either the round or the hex head, dimpling isn't a huge issue. You should, after locking in and before extraction, see the impression of about half the screw, maybe a bit more. You're looking for about a mm of headspace, and the round head screw is about 2.5 mm into that area.

The best of both worlds, of course, is to modify the dispersion screen/block and get a new flat head screw.