Switching from a double to a single without changing the grind?

[hgs]

hello - first post here.... thanks for all the great tips so far (and i've come pretty far without any questions)... but...

i recently set up an anita and a macap m4... i am able to dial in good doubles (from normale to ristretto). my grind and tamp was perfect for a 25sec 2-2.5oz double. then i tried the same with a single PF, and failed miserably - about 5x in a row.

first time - filled to top of pf, scraped off, tamped w/ 30lb of pressure (same as i had done w/ the double - using various crutches discussed on this site), and i couldn't even get the PF attached (no headroom).

second to fifth time - tried measuring grinds out so that there was appropriate headroom, always using 30lb tamp - shot would start a little earlier than w/ the doubles, and within 12secs, would start gushing. pulling off the PF after the shot would actually leave the puck attached to the group-head screen.

if i hadn't just nailed the doubles, i would have thought to grind more fine.

shouldn't i be able to switch from from a double to a single without changing the grind? is there something else i'm missing? should i just forget the single PF?

greg

[John P]

There are two schools of thought: (maybe more...but these are MY two )

1) Adjust your grinder slightly coarser. On the Mazzer it equates to about 2-2.5 notches.
2) Learn to tamp by "feel". You have to tamp a little lighter on the single.

Conventional wisdom would say, adjust the grind. This will probably be the best/easiest path for the Home Barista. But at home, or at a caffe, you must make sure to clean the 'double' grounds out of the grinder--the ones that tend to hang up in the chute. If the Macap cleans out better than the Mazzer, then no worries.

Learning to tamp by "feel" is also worth learning. Unless you have drastic changes in humidity, age of beans, etc. that REALLY cause you to change the grind by a noticeable amount, you can learn to feel how the grounds in the portafilter yield to your tamping, and in turn learn how much pressure to apply. In the case of switching from double to single, this is what I often do so as not to have to adjust the grinder anytime someone orders a triple.

We don't do split shots here. I'd rather pull a good single.

[cannonfodder]

People tend to overdose the little single basket. Overfilling the basket can cause the surface of the puck to scrape against the shower screen when you lock it in. That will cause massive channeling and fast shots. Don't fill the basket as full. Try tightening up your grind and lower your dose. Keep the pre tamped coffee dose below the top of the basket, then tamp flat and see what happens.

It took me a lot of practice to get the single down pat. My biggest problem was forcing myself to down dose the basket.

[John P]

I would just say "dose the correct amount"

[another_jim]

If you finger stroke dose, that is, fill the basket loosely and swipe across with your finger, you will never get the same grind setting for the single and double. A given manufacturer will create baskets that use the same grind when dosed at 7 and 14 grams, which is usually well below the rim level, especially for single baskets.

Most shops don't do both signals and doubles, and most home baristas who use both baskets will do them on alternate days. Luca Costanzo, a moderator on CG, is a working barista, and he and his coworkers have designed an ingenious set of curved scoops to swipe across the baskets. They have one for the single, and one for the double, chosen so that the same grind setting can be used.

[luca]

Most shops don't do both signals and doubles, and most home baristas who use both baskets will do them on alternate days. Luca Costanzo, a moderator on CG, is a working barista, and he and his coworkers have designed an ingenious set of curved scoops to swipe across the baskets. They have one for the single, and one for the double, chosen so that the same grind setting can be used.

Hey, that's what I was going to say! To be fair, though, Scott Callaghan invented them. Part of the idea is also that you can switch tools to take out successively less so that you can get perfect pours without adjusting the grind as the coffee ages. Personally, I just adjust the grind!

Cheers,

Luca

[DC]

To be fair, though, Scott Callaghan invented them. Part of the idea is also that you can switch tools to take out successively less so that you can get perfect pours without adjusting the grind as the coffee ages

Are these available generally or are they a one-off bit of kit? I don't know what they look like but I've been trying to design my own one-piece 'leveler' which is adjustable for different levels of under-dosing.

Thanks,
DC

[timo888]

shouldn't i be able to switch from from a double to a single without changing the grind?

Your underlying assumption is that the double and single baskets, when dosed, would have the same flow characteristics; but, all other things being equal, any differences in the effective egress of the filters would cause the baskets to have a different flow. Unless you can compensate for such differences by tweaking the dose and/or tamp, you would have to adjust the grind.

Regards
Timo

[jesawdy]

All, Teme just blogged a bit about Aussie Scott Callaghan's leveling kit on Sunday, February 25, 2007, at http://www.espresso-passione.com/

Here's what they look like:


pic from Teme's http://www.espresso-passione.com

I went to the web address, but nothing setup yet.

[luca]

I went to the web address, but nothing setup yet.

Are these available generally or are they a one-off bit of kit?

Scott's email should be on the webpage.

I don't know what they look like but I've been trying to design my own one-piece 'leveler' which is adjustable for different levels of under-dosing.

The single piece leveller that looked like an exponential curve was the predecessor to the multiple-piece levelling kit. It wasn't as easily useable as the multi-piece kit.

Cheers,

Luca