Single shots bad, double shots much better - why?

Beginner and pro baristas share tips and tricks for making espresso.
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DaveLSM
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#1: Post by DaveLSM »

At the risk of asking a newbie question that may have been asked in the past....

Have got my new-to-me machine plumbed in and operating nicely, and was struggling for a few sessions with my single portafilter, getting very inconsistent results. I have read and re-read the basic stuff on dosing, grind, etc, and think I have the grind right, and the dosing very close. I don't have an accurate gram scale, but do have a small kitchen scale, and while it lacks adequate resolution for manhattan-project calibre science, I think I am in the ballpark, dose wise. My tamping is inconsistent and I can clearly see when I tamp too hard.

For no particular reason, I switched to my double portafilter this AM, and pretty much nailed it. Second shot was excellent (relatively).

Is this typical and if so, why? is the bigger puck more forgiving? (i can see that it would be easier to get the dose right, in proportional terms) If not simply the random nature of the universe, (or me) what is going on here?

Thanks all.

Dave
La vita e troppo breve per mangiare e bere male.

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canuckcoffeeguy
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#2: Post by canuckcoffeeguy »

Hi fellow Canuck. Singles are notoriously harder to pull. That seems to be the consensus. An overwhelming majority of home baristas, and cafe baristas(outside Italy), just pull doubles.

I have little experience even trying to pull singles, so I can't even explain why it's hard. Other than you'll need a different tamper for a single, you'll have to grind finer than a double to achieve a good flow rate with the lower dose. And the single basket itself has a different shape. I'd just stick with doubles since you're already finding it easier, like everyone else.

DeGaulle
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#3: Post by DeGaulle »

The stock single basket that came with my machine has a small diameter at the bottom, is tapered and expands towards 58 mm halfway along the basket height. If I fill the basket to the recommended dosage of about 8 grams, then when I tamp, I hit the basket metal rather than the puck. If I fill the basket to the rim, it is overloaded and the PF won't lock in properly.

Many people on this forum and others like it will probably advise you to just forget about the single basket and I am one of them. Yes, it is far less forgiving than a double basket. Whenever I make an espresso just for me, I pull a 1.5 oz double shot from 15-15.5 grams of ground coffee. If I pull shots for 2 people, I use a 17 grams double basket and pull a slightly larger volume.

Another bit of advise would be to get a digital scale with a 0.1 gram resolution or better. Especially in the beginning it helps big time to get consistency in your shots.
Bert

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canuckcoffeeguy
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#4: Post by canuckcoffeeguy »

DeGaulle wrote: Another bit of advise would be to get a digital scale with a 0.1 gram resolution or better. Especially in the beginning it helps big time to get consistency in your shots.
+1 on the digital scale with 0.1g sensitivity. This is pretty much essential equipment when learning. It keeps the dose variable consistent. You can also weigh your shots, rather than measuring by volume. Weighing is much more accurate than by volume since crema varies widely between coffees and pulls. The varied volume of crema will skew your measurement. So just weigh.

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DaveLSM (original poster)
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#5: Post by DaveLSM (original poster) »

DeGaulle wrote:The stock single basket that came with my machine has a small diameter at the bottom, is tapered and expands towards 58 mm halfway along the basket height. If I fill the basket to the recommended dosage of about 8 grams, then when I tamp, I hit the basket metal rather than the puck. If I fill the basket to the rim, it is overloaded and the PF won't lock in properly.

Many people on this forum and others like it will probably advise you to just forget about the single basket and I am one of them. Yes, it is far less forgiving than a double basket. Whenever I make an espresso just for me, I pull a 1.5 oz double shot from 15-15.5 grams of ground coffee. If I pull shots for 2 people, I use a 17 grams double basket and pull a slightly larger volume.

Another bit of advise would be to get a digital scale with a 0.1 gram resolution or better. Especially in the beginning it helps big time to get consistency in your shots.
Thanks gentlemen, it helps to know that I appear to be on the right track at least. (I notice you both have Bezzera machines - very nice. I was zeroing in on those before I found this LSM commercial beast in the local online classifieds.)

Ryan, cool blog. Great photos. Unsurprisingly perhaps, it seems we enjoy travel similarly.

Borrow or buy, the scale was in the cards for sure as is calibrating the doser volume to baseline dose weight (three cycles seems very close already).

DeGaulle, you have described my single portafilter accurately, though the bakelite OEM tamper I have is quite a bit smaller than the portafilter, so there is no interference. I think I will either cut down one of my two PFs to make it bottomless, or just leave the solid backflushing basket in one.

I think I will find a closer fitting tamper also, I can see how that would help.

Once I get this close empirically, and understand the variables well enough, I'll be happy tweaking by observation and "feel". Getting there... Thanks again.
La vita e troppo breve per mangiare e bere male.

lcats
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#6: Post by lcats »

While I usually pull doubles, sometimes I only want a single, and at times I have apparently lucked out and gotten something quite acceptable. I think that if I was only pulling singles, I'd have the workflow down pat: grinding finer, finding the exact number of grams of a particular roast which would work with my 7gm VST single basket, and improving my use of the backend of the LM metal tamper, which just fits that VST's lower cavity. However, since it might be less than once a month that a single is needed, my mileage varies all over the place--I am forced to make guesses on the parameters, and am often wrong. It would be a healthy exercise to perfect this, but motivation is largely lacking.

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bluesman
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#7: Post by bluesman »

DaveLSM wrote: the bakelite OEM tamper I have is quite a bit smaller than the portafilter, so there is no interference.
This is almost certainly a problem for you. Plastic tampers can work OK, but only if they fit the basket well. It's a lot easier to tamp consistently with a good metal one, but even the best one won't do the job right if it's grossly too small.

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DaveLSM (original poster)
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#8: Post by DaveLSM (original poster) »

Borrowed a scale from a friend today and checked my doser-estimating - was as high as 18g, generally around 15-16, but even without pre-weighing, the leap in quality vs my jura superautomatic is quite amazing, just by being close and getting it somewhat right.
Served us some delicious whole milk cappuccinos, and some espresso shots and he was quite blown away.
Quite something really... the difference.
Agreed on the tamper for sure, its a bit fiddly, and feels cheap. I'm too old for stuff like that - dull knives, cheap tools, ikea furniture, bad wine, annoying music, bad coffee, unreliable cars, etc...
Gonna' really clean my grinder tonight.
Thanks all for the guidance, very much appreciated.

Dave
La vita e troppo breve per mangiare e bere male.

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yakster
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#9: Post by yakster »

Some things to think about when pulling singles from the perspective of a home lever user.
  • Try a lower brew temperature, there's less grounds to absorb the heat of the brew water. I believe I read this in Scott Rao's "Professional Barista Handbook"
  • A shorter pre-infusion or no pre-infusion can work better with singles, I believe this is related to the temperature issue
  • I've seen videos showing Baristas pulling shots with a spouted portafilter and just letting one of the streams run into the drip tray when they only needed one singe, no need to change the grind, temp, etc. if they're already dialed in.
I actually like pulling singles, but it's pretty rare that I do so these days.
-Chris

LMWDP # 272

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DaveLSM (original poster)
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#10: Post by DaveLSM (original poster) »

Kinda makes sense, less coffee means less resistance (its cumulative), its harder to get the thinner puck to distribute evenly (made worse by the small tamper), it gets hotter quicker, any variance in mass is proportionately greater... etc. Anyway, I cleaned and dialed in my grinder to reliably dose 14g with 3 clicks, and the doubles are now pretty consistent and delicious.

Was thinking about my original question, and in the end, as with women and beauty, the "why" really doesn't matter much... ;-)

Dave
La vita e troppo breve per mangiare e bere male.

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