I finished reading the Titan Grinder Project thread, and I had a few questions:

1. Someone mentioned thwacking the dose DURING the grinding process. I've been gently turning the doser AFTER all the grinding is done, so that coffee lands neatly in the PF. Will the former method give me better distribution? Of course, with my single dosing, the fact is that more than half of the ground coffee sits in the chute, and has to be brushed out into the doser after the grind anyway.

2. Several folks mentioned a bitterness to the MXK's shots. I have noticed a bitter finish to some of the shots but figured it was still about my technique. Is there a way to mitigate this with the MXK?

3. Once again, I read that the MXK produced better shots in the 13-14g range, lower than I typically dose these days at 15-17g. (Hairbender at 20g). Why would the lower dose produce better results?

4. Currently, my process is to single dose, then go from the doser directly to PF. My technique now is very non-interventionist at this point: I may or may not use my palm in semi-circular miovements to even out the mound, then tap the bottom of PF once or twice on the padded countertop, and then tamp. No WDT. The pours look good from my LM basket ridgeless basket. Is this what most folks are doing with this or other large dosered grinders? Are some of you dosing into the basket first, and then putting it in the PF?

I haven't re-read the TGP thread to refresh my memory, but will comment generally:

innermusic wrote:I've been gently turning the doser AFTER all the grinding is done, so that coffee lands neatly in the PF. Will the former method give me better distribution?

In my experience, thwacking the doser handle while paying particular attention to landing the coffee dose around the perimeter helps clump-prone grinders dramatically. A simple shake-shake to level is all that's required for the most even, clump-free grinders (e.g., Mazzer Robur).

innermusic wrote:Several folks mentioned a bitterness to the MXK's shots. I have noticed a bitter finish to some of the shots but figured it was still about my technique. Is there a way to mitigate this with the MXK?

Here's a good place to start: Espresso 101: How to Adjust Dose and Grind Setting by Taste. You didn't mention the brew ratio or temperature, but increasing the former and/or lowering the latter could help.

innermusic wrote:Currently, my process is to single dose, then go from the doser directly to PF.

I would avoid single dosing until you've mastered your setup. Some grinders single dose just fine, some require a small weight like a tamper, others will meander. I remember the MXK being a "benign clump" monster, but I never tried it single dosing... maybe those clumps aren't so benign in that case.

[corrections from owners welcome on the last point]

On the MXK & MXC, brush the throat while grinding using ColorTrak highlighting wands bent at a slight angle. After grinding, clear throat, dose with moderate thwack, moving basket for even distribution. Gentle shake, tamp. Enjoy.

IMO, single dosing impacts mouth feel negatively, as does a bottomless PF for the coffees and shots styles I prefer

Few of the big grinders - let alone the Titans - arrive prepared to take on the demands of home use. So getting the benefits of a commercial grinder in your kitchen is an exercise in modifying them with hoppers smaller than a tanker truck, single dosing etc. while still leaving in place the critical parameters for which their original design is optimized.

I don't have an MXK myself, but my M7K bears some family resemblances and I settled on that Macap given its overall friendliness to such modifications. Due to the lower RPM motor, it doesn't throw the grounds out of the chute/throat, but its opening is nice and wide so sweeping is easy and quite thorough. Via use of a pastry brush (Ateco #60200) and three quick bumps of an auxiliary momentary switch I installed (replacing the auto-hopper fill vane/switch and then some) I'm getting output within 0.1g of the input most of the time when single dosing.

My modified hopper assembly is also way-off-Broadway compared to its original construction and size, but with a constant-pressure plunger inside a cylindrical insert, the grinding behavior acts very consistent, at least as measured by shot timings (although I don't have a dimensioning electron microscope hanging around to quantify this).

But even tasting carefully, I haven't personally found any kind of systematic bitterness or leanings in that direction. For sure, you can go as bitter as you like, but that's using you-know-what for you-know-how-long at you-know-what-temperature. On the contrary, I'm getting a nice richness and sweetness I couldn't achieve with the smaller flat-burr grinders I'd used before - though I would never suggest this one experience is conclusive.

All that said, Ike's comment is interesting and well-founded from his considerable experience and I suspect he's correct in general. Again, however, your mileage probably depends on the degree to which any particular home-mod hopper/plunger for single dosing is able to simulate a stock hopper, moderately full. For example, a plunger/weight will likely need to get all the way down to the tops of the burrs - and even down into the open space between the inner and outer sets if possible - for maximum effect.

My guess is that variations around items such as these will make more difference - since they will affect the grind itself - than sweeping or thwacking during, versus after, the grinding process.

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So as pictured, I have cut a plastic "hopper" and use a plastic bottle of arginine pills as the plunger. The pill bottle fits perfectly into the hopper and I never change the weight (don't use the pills), in order to have one more aspect of consistency. The bottle is nothing close to the weight of a tamper, and it does the job of sitting closely on top of the beans.

Nonetheless, the last beans to go thru the grinder are going to be ground differently, as there are less beans for them to bump in to. I really think I'm compromising grind with the single dosing; I am well aware that the results will be better if I have more beans in the hopper at all times, and weigh the ground coffee on the way out instead of the beans on the way in, BUT how does one make continuous adjustments to the grind with beans in the hopper, given that the machine has to be on when the grind is adjusted?

HB wrote:Here's a good place to start: Espresso 101: How to Adjust Dose and Grind Setting by Taste. You didn't mention the brew ratio or temperature, but increasing the former and/or lowering the latter could help.

Tried the gauntlet of temperatures, from 194 to 200. The lower temp didn't remove the bitterness. But I did go from a tight-ground ristretto with ratios of 75% to 100%, (dosing 14-17g) to a coarser grind and that helped.

cafeIKE wrote:On the MXK & MXC, brush the throat while grinding using ColorTrak highlighting wands bent at a slight angle...

Ike, true enough, those sure look even better than what I've been using. Thanks for the tip.

Not to state the obvious, but the bitter could simply be the coffee you are using. Have you tried a different blend from a different roaster? Bitters are also a symptom of over extraction from some minor channeling. Timing can also play into bitter, try reducing your brew time by 2 or 3 second increments and see what happens. Some coffees just work better with a short (22-23) second extraction.

When changing grinders I would often find that I no longer liked a coffee that I previously enjoyed. The change in grinder would bring out different flavors, some of which I liked and some of which I did not. I would often find a new favorite after an upgrade

Thanks Dave. Actually I've been trying new blends and coffees. Some better than others.

Perhaps I am making this sound bigger than it is. The bitterness is not overpowering or anything close to that. It's in the finish only. Not the end of the world, but it is there and noticeable. Less with some coffees, less with some pulls. But there.

I would still like to get some tips on how one makes adjustments to the grind with beans in the hopper, given that the machine has to be on when the grind is adjusted. Might be obvious, but it's something I never had to deal with with the Vario.

Steve,

Just get the single basket that came with your espresso machine, stick it on an spare group rubber gasket and you will see that it perfectly fits on top of the collar of your MXK preventing popcorning.

By the way, it is always recommended that your grinder is on ( with or without beans) while you change the grind settings.