HB wrote:Experience is a good teacher, eh? Assuming you can duplicate his results, I am interested in the diagnosis of the problem. Our guesses were all over the map.

Absolutely.
There are two standard responses I use when those new to espresso have problems that they can't seem to straighten out:
1) Grind finer and tamp lighter
2) Get someone who knows how to make espresso come over and play with your equipment.
I have experienced both and have benefited from both as well.

luca wrote:Hi Jeff,
(b) Dose: Try more coffee and a coarser grind. Don't worry about the whole headspace thing - worst case scenario, you screw up a few shots and then backflush. If dosing proves to be problematic, you might need to try a bigger basket.

i can't believe I haven't thought of this. I have dosing issues to the point my best pours are a) fill the basket slightly over the top b) do an even scrape c) tamp
Now the following has given me some good consistency however I can't get more than a nice 1.5oz shot. It seems I need more coffee -however this would blow my consistency trying to dose, settle scrape off leaving a mound on top etc. I just received a 3shot basket and am going to try grinding to just over the top, leveling like before, tamping. If I'm right i will end up with a dose of coffee such as a large double but sitting in the triple basket. Going to fire up the machine and see what happens, I'm hoping with the triple basket I can hit a solid 2oz double maybe a tad more. I basically want a good 2oz for my milk drinks and big cups. The 1.5-1.7oz almost carries my cups but there is a tinge of too much milk. I'll report back!

Ok this is my first attempt and it's a bit nasty.. Maybe a WDT would help here feel free to diagnose..

[gvideo]http://video.google.com/videoplay?docid=-5169520009563822628[/gvideo]

jeffg wrote:i can't believe I haven't thought of this. I have dosing issues to the point my best pours are a) fill the basket slightly over the top b) do an even scrape c) tamp
Now the following has given me some good consistency however I can't get more than a nice 1.5oz shot. It seems I need more coffee -however this would blow my consistency trying to dose, settle scrape off leaving a mound on top etc. I just received a 3shot basket and am going to try grinding to just over the top, leveling like before, tamping.

This sounds opposite of my experience. I have found that the VBM has the best results when "UNDER-DOSING" just a bit. Using a little less coffee than "full" give the coffee some headroom to expand a bit during the pre-infusion and early ramp up, and it allows a finer grind. My scale only weighs in full grams, but around 14 or 15 grams is a good place to start. I just estimate by not completely filling my basket by eye.

If I have gathered enough from this forum, it all means that it gives the coffee the ability to pass some of the fines to the bottom of the puck (and the time to do so as the coffee expands) which creates a bit of resistance to slow the flow and the finer grind allows a better extraction.

As I said, it works quite well for me.

Randy G. wrote:This sounds opposite of my experience. I have found that the VBM has the best results when "UNDER-DOSING" just a bit. Using a little less coffee than "full" give the coffee some headroom to expand a bit during the pre-infusion and early ramp up, and it allows a finer grind. My scale only weighs in full grams, but around 14 or 15 grams is a good place to start. I just estimate by not completely filling my basket by eye.

If I have gathered enough from this forum, it all means that it gives the coffee the ability to pass some of the fines to the bottom of the puck (and the time to do so as the coffee expands) which creates a bit of resistance to slow the flow and the finer grind allows a better extraction.

As I said, it works quite well for me.

Are you getting 2oz with 14-15grams? With that kind of dose my shot is done for at around 1.5oz. at around 20seconds. I guess I could try a slightly coarser grind but i think last time i did that is still petered out at 1.5oz. Can a pressure adjustment help add more volume and a longer shot?

jeffg wrote:Ok this is my first attempt and it's a bit nasty.. Maybe a WDT would help here feel free to diagnose..

Jeff, your video reminded me of this from an article here on HB:


Have you read through this article? Aside from that, maybe try using less milk with your drinks. I have trouble getting full 2oz shots, too. I just don't worry about it and enjoy the slightly shorter shots my machine does produce! Good luck.

Justin

well i got my 1.5 ouncers tasting nice so may just hunt for some slightly smaller cups.. In the meantime may keep experimenting..

jeffg wrote:Are you getting 2oz with 14-15grams? With that kind of dose my shot is done for at around 1.5oz. at around 20seconds. I guess I could try a slightly coarser grind but i think last time i did that is still petered out at 1.5oz. Can a pressure adjustment help add more volume and a longer shot?

I don't worry about volume so much and worry little about time as well. It's the taste that counts.
I drink milk-based drinks, but I do use a demitasse spoon to sample the stream during the pull, so I do know what tastes good and what doesn't. I get about two ounces in about 25-35 seconds, but often let it run a bit longer since it cuts through milk better.

Let your tongue decide what works for you and not a measuring cup nor a stop watch.

Randy G. wrote:I do use a demitasse spoon to sample the stream during the pull

Interesting, from my noob perspective can you explain? I am assuming the last 5 seconds or so you take quick tastes? not sure..

I usually pull around 1.5-1.75 ounce doubles with 14-15 grams of coffee. When I see the dreaded donut of death (outside in extraction with a dead spot in the center) I down dose, grind finer and tamp lighter. I actually tamp just using two fingers, three if you count my thumb. I use a very light tamp now, quite a departure from my early days when the table would creek when I tamp. I have gone from the 800 pound gorilla to the butterfly tamp.

I have also gone from the fill the basket to the top and level to the fill just above the basket retaining clip ridge, thump three times on the table and tamp. On my VBM, I use 14-15 grams give or take one depending on the coffee. Using my Reg Barber tamper, the top of the tamper sides are just below the top of the basket.

Another question, what is your pump pressure set at with a blind basket? I thought I heard something in the video that may explain some things. Dan pointed out the spring OPV issue, VBM had a production run that had some bad springs in the OPV. Those machines have a sound to them, the OPV sputtering as the pressure builds and during peak pressure. I thought I heard that same sound in your video, but it could also be a cup on the cup warmer.