Help with channeling - Page 5

Beginner and pro baristas share tips and tricks for making espresso.
Nate42
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#41: Post by Nate42 »

If you do decide to go the grinder upgrade route, my understanding is super jolly burrs are drop in replacements for the mini-e, they don't require the SJ carriers like the standard mini does. You could give that a try for a roughly $50 investment.

I don't know how that compares to an actual super jolly (and indeed I recently started a thread asking that very question) Mazzer Mini with Super Jolly burrs vs. actual Super Jolly? But it sounds to me like its worth a try. The only reason I haven't done it yet is with my standard mini I would need to lay out more cash to replace the carriers.

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RapidCoffee
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#42: Post by RapidCoffee »

williamsavona wrote:I am using a scale however I am about ready to throw it out my kitchen window out of frustration! It is not reliable and I find it to be inconsistant by as much as a couple grams.
Peppersass wrote:Although others may disagree, my conclusion is that most of the problem is with your grinder.
You are using good coffee, and there are no obvious flaws in your technique. That leaves equipment issues.

1. Check the dose weight when you get the new scale, and keep it to 15-16g for the time being.

2. It's worth double checking the actual brew pressure on your espresso machine with a portafilter gauge. You can build one for $10-15 with hardware store parts.

3. I'm sure the Mazzer Mini is a capable grinder, even if it's not a large conical. But I concur with Dick: this smacks of grinder issues. You might try to pull the burrs, clean out any compacted grinds, and then make sure they are reseated properly upon reassembly.

Good luck!
John

Anvan
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#43: Post by Anvan »

jontyc wrote:What I was thinking could work, but I don't have a convex tamper to test it, is to do a light tamp with a convex to spread the grinds slightly towards the perimeter, then a final tamp with a flat?
The idea of the convex tamper in general is to combat edge-favoring by making the coffee deeper at the basket sides. This presumably counters the water's favoring the easy route down the basket sides and lowers the pressure requirements a little in the center. The hope is that the flow will thereby be equalized between center and edge.

Success here will depend on getting the balance just right, but while that is possible, there is never a free lunch: it means that you are also compromising the extraction to at least some degree since it will now be necessarily different at the edges compared to the center since the edge coffee will be deeper.

The idea of using the convex tamper as a "spreading" device would fit the notion of equalizing the center thickness of the cake with its edges, given a curved/bowed basket bottom and a curve-bottomed tamper. But finishing with a flat tamper would likely defeat the purpose though, since even with some inward migration of the grinds during tamping (due to the tamping pressure that engages the edges first) the edges will be denser and more heavily packed than the center. The result may prevent edge-favoring of the brew water, but will also cause the same unwelcome extraction differential as described above. So in some fashion, you are trading one extraction problem for another. Now of course that trade-off may be to your advantage (depending on the degree of the edge channeling or donut problem) but you still won't be getting what you really want, which is equal and optimal edge-to-edge extraction.

One place from which you can get a clue is VST's basket design, where you can see that the perforations cover the basket bottom nearly edge-to-edge (compared to typical baskets, where the perforations are absent at the edges). This is not accidental: VST evidently concluded that missing edge exit holes limit the extraction of the full coffee puck. The missing perforations in typical baskets may discourage some edge channeling, but this is at the cost of the edge coffee not fully participating in the extraction.

This factor may make the VST baskets more demanding to prepare by requiring more evenness - which has been amply documented. But I'm not so much making a pitch for VST as suggesting that it's an uncompromising design with a great deal of real research (compared to mere thought experiments such as this post of mine) that can inform us by example about getting the best out of a basket of coffee. This message is that optimal flavor and body require consistent edge-to-edge flow through a puck of even thickness. So my conclusion has to be that a convex tamper is, at best, a device that may remediate one problem but will never enable the very best that the coffee, grinder, machine and personal skill could otherwise accomplish.

jontyc
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#44: Post by jontyc »

A very interesting read. Thanks Anvan.

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williamsavona (original poster)
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#45: Post by williamsavona (original poster) »

Quick update:

Distribution:

My curiosity got the best of me and I decided to throw some more money at my distribution problem. This weekend I picked up a couple VST baskets (18g and 20g) as well as a Cafelat 58.35mm tamper (man I didn't realize how crappy the aluminum tamper that came with the Rocket was until I felt a real steal tamper).

This could just be a fluke but I poured three shots this morning, one right after another, and they all looked like this one. I am still making adjustments to the grind (see below) but the distribution seems to be greatly improved with these new tools. Going to be playing around and testing all day so feel free to ask me to try things.

18g of beans, 18g VST basket, WDT, with 25.5g of espresso out.
Mazzer Mini E

I hate my grinder. I hate everything about it. Of all the things I've spent $800 on, this is easily the most frustrating. Main complaints:
  • What's the point of having a stepless grinder if making very small adjustments is nearly impossible. I am getting better but jeez is it hard to make that collar move in small increments!
  • The portafilter holder is a joke. Why put it there? No one is going to be able to grind directly into the portafilter with this thing's distribution problems
  • Did I mention the terrible distribution?
I am seriously considering selling it to whatever sucker would actually want this thing and replacing it with something that allows me to single dose and get nice even distribution directly into a portafilter with minimal fuss but I can't spend more than $1000 on a grinder right now. Dose that grinder even exist? Should I try replacing the burrs with the ones from the Super Jolly before going with something new?

Nate42
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#46: Post by Nate42 »

That last shot looked pretty good to me. It wasn't text book perfect, but it was pretty nice. If you can do that routinely and you like the taste, relax and enjoy life is what I say. :)

Regarding your mini complaints: adjusting the collar gets easier with practice. Take off the portafilter holder if you haven't already, nobody actually uses those things. You'll be able to get better distribution with it out of your way. Were I in your shoes, I would try out a set of super jolly burrs before I gave up entirely, but I doubt that would fix your distribution issues.

Good luck.

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JmanEspresso
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#47: Post by JmanEspresso »

re the adjustment collar- Mazzers adjustment collar CAN get stiff, but personally, Ive never had trouble going from a "bump" to a "dent". Ive always been able to make the exact adjustment I want on a Mazzer, and when the collar starts getting stiff, its time for a clean.

Take the collar off, take the upper burr carrier out.

Using a toothbrush, or paper towel followed by a toothbrush, completely wipe clean the threads on the adjustment collar. IF there is lube/grease on the threads, wipe it off. The paper towel will get most of it, the toothbrush will get the rest.

Using the same tools, wipe clean the threads in the burr chamber.

The key here, is you need to get both threads COMPLETELY clean. Anything in the threads, like stray coffee grinds, make it harder to adjust the grind collar.

(While you're inside, inspect the burrs, UP CLOSE and with a magnifying glass, for damage to the cutting edges. It should feel sharp. The edges shouldn't look rolled over or have major dings in them. If you can take close up pictures in high-rez, do so, so we can see.)

When putting her back together, BE CAREFUL not to cross thread the adjustment collar. IT should thread in smoothly, you shouldnt need to force ANYTHING, AT ALL.


This should make it a little easier to turn. IF you are still finding it hard to make minute adjustments, then take it back off, and wrap the adjustment collar threads in a few wraps of Teflon Tape. Too much will make it worse, but the right amount will make the collar a piece of cake to move smoothly.

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williamsavona (original poster)
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#48: Post by williamsavona (original poster) »

JmanEspresso wrote:when the collar starts getting stiff, its time for a clean.
The grinder is new and has had less than 10 pounds of coffee through it so I have a feeling it actually just needs some more use to loosen up a bit. But please correct me if I'm wrong, I am new to this.

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cannonfodder
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#49: Post by cannonfodder »

The Mazzer is more than capable of pulling good shots. It was the gold standard for home grinders for years. With only 10 pounds through it you may be chasing a white rabbit. A new grinder takes several pounds of coffee to settle in. The portafilter holder was the first thing that came off my grinder. With it removed you have room to move the portafilter around so you dose around the perimeter of the basket instead of a big pile in the middle. The adjustment has to be tight to keep it from drifting. You should of had a little adjustment handle that screws into the adjustment ring. That makes adjusting much easier. Do you have a pressure regulator on the water mains? What is the pressure on the water supply?
Dave Stephens

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williamsavona (original poster)
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#50: Post by williamsavona (original poster) »

I completely agree that the Mini E is very capable it just requires a lot of fuss if you single dose. Even if it distributed coffee perfectly into the basket I'd still find the chute sweeping routine to be a slight annoyance. Clearly I need to reset my expectations for coffee grinders. Again, I am totally new to this. :) I'll be the first to admit I'm anal about things (do I really need to use a hand-vac to clean the chute when I'm done pulling shots?) and that plays a big part in why I am not liking the grinder. With time I think we'll learn how to get along just fine.

I removed the portafiler holder today. Much better.

I haven't plumbed in the machine yet; I am still getting all the necessary parts together.

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