I got my Robot (my first espresso machine) last week, and have enjoyed playing with the various facets that go in to a good pull.

I don't yet own a grinder (still shopping around and can't commit!) so I've been using the grinder at our local Whole Foods. My first bag of beans I set the grinder to the "Espresso" setting, and ground away. I was getting nice, 25-30 second pulls, but the espresso was more bitter than I was hoping. I read where that could be because of too fine a grind.

So my next bag, I set the grinder one notch coarser. Looking at the result, I worried that it hadn't really made a difference, as everything looked just as powdery as before. HOWEVER, when I tried this new bag for the first time (and every time since), the espresso is FLYING out of the Robot in like 5 seconds, spraying everywhere. I can't achieve close to 9 bars of pressure.

This seems to be the result of too coarse a grind, but I honestly can't see any difference between this bag of ground coffee and the previous one. Certainly nothing to account for the radically different flow rate. I haven't changed my dosing (18-20 grams or so), so I'm wondering if there are any other variables I should be considering.

Buy your own grinder aimed at espresso (single dose) if you want repeatable results. This will change your game so much so you will end up with a collection of them.

+1 ; and buy beans with a roast date no more than 2 weeks old (unless you are sure you'll go through them within 4 weeks post roast.
Typically notches on grinder mean that you'll never be able to hit the right spot, expecially with a shop grinder that covers a range from boulders to dust and all of that with usually a small change in setting.

mwelch wrote:...I've been using the grinder at our local Whole Foods.

Unless you use the pressurized basket (the one with the single tiny hole in the bottom), preground coffee inevitably leads to inconsistent and disappointing results (search on "preground coffee" in the forums and you'll find countless confirmations of this point).

Well, mine isn't "preground" in the sense that I think the pressurized basket is intended for. That's for those bricks of coffee you can buy. Mine is just ground (poorly, apparently) all at once.

I am still confused about why such a very slight (pretty much visually imperceptible) change in coarseness would result in such a drastic pull failure. Regardless, I think the advice to finally buy a grinder is a good one.

For me, preground coffee = not ground within minutes of brewing, grind setting not adjustable based on the pour. Of course, bricks of preground coffee are the extreme, but coffee ground in store definitely counts as preground in my book and is very unlikely to yield good results.

This video elaborates on this point.

HB wrote:For me, preground coffee = not ground within minutes of brewing, grind setting not adjustable based on the pour. Of course, bricks of preground coffee are the extreme, but coffee ground in store definitely counts as preground in my book and is very unlikely to yield good results.

Thanks for the feedback. Going to commit to a grinder today and get one ordered!

HB wrote:Unless you use the pressurized basket (the one with the single tiny hole in the bottom), preground coffee inevitably leads to inconsistent and disappointing results (search on "preground coffee" in the forums and you'll find countless confirmations of this point).

100% true! I've had the same issues with my Robot. Spraying. Channeling. Bitter espresso. It was awful. I have hand grinders but I got tired of using them so I went to my local coffee house bought bags of Counter Culture Big Trouble whole beans. Each week I would buy one bag and have the beans ground in front of me by the barista. I've done this quite a bit and the barista has used different grind settings for me. No matter. I could never pull a great shot with my Robot. Then I went back to my hand grinders and, wa-la, the situation is solved. I don't know why. Maybe it's because the grinds are still light and fluffy and have not been compacted. Either way my pulls are consistent with no channeling, spraying, and with a tail flowing from the middle of my bottomless portafilter. I am in heaven once again.

If you don't want to grind coffee by hand I have two recommendations. The first is the Niche Zero. Much has been written about this grinder and it shoots way above its price point. I've decided to wait and not buy the Niche, however. I would rather save my money and get a Kafatek MC3. Yes, it's more than double the cost of the Niche Zero but the Kafatek is a forever, desert island single dose grinder.

If you're looking for something that's a little cheaper than the Niche the Baratza Vario is a very good -- and is available immediately. Chris, Clive, and the other usual places have it at under $500. I have mine for 2 plus years without any problems.

davidhunternyc wrote: I would rather save my money and get a Kafatek MC3. Yes, it's more than double the cost of the Niche Zero but the Kafatek is a forever, desert island single dose grinder.

You will need a generator also. An HG-1 would be my choice.