WDT changes extraction time drastically

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RockyIII
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#1: Post by RockyIII »

My Mazzer Super Jolly Electronic grinder, with just a few pounds of beans through it so far, produces a lot of clumps, but they are very soft and fall apart with a slight touch. I use the bean hopper as designed and have been grinding directly into the portafilter basket with an OE cylinder on top, weighing at 18 grams, distributing with a finger, and tamping with a 25 lb. calibrated Decent Tamper. The shots are 36 grams in a very consistent 30 to 32 seconds and have been tasting great. When observing the bottomless portafilter, the flow looks pretty good but usually not perfect. The flow without WDT is vastly better than what I used to get from my HG-1 without WDT, for which I found WDT to be mandatory.

Just for grins, I ground into a small cup, performed vigorous WDT with a small spoon and then a toothpick, and then dumped the grounds into the portafilter basket, distributed, and tamped. I noticed that the level in the basket was lower than when using my usual method, which must mean that the grounds were a good bit more tightly compressed. The extraction time jumped from a normal 30 seconds all the way up to 55 seconds. When observing the bottomless portafilter, the flow took so long to begin that I wondered if it was totally choked. Then the flow began and looked quite perfect other than being slow. I am not very skilled in tasting, but I know what I like and the shot was not bad. The next logical step would be to use a coarser grind along with WDT, but I have not tried that.

Is it typical for WDT to cause such a dramatic difference in extraction time? I do not want to start using WDT on every shot, and I really thought there would be little if any difference. Now I wish I had not even tried it. Heh. Does this mean I am getting a lot more channeling than I think I am, or does it have more to do with the tighter compression?

Rocky

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AssafL
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#2: Post by AssafL »

The difference in performance (especially when using a refractometer to measure EY) between a WDT and non-WDT pull shows the quality of grind normalization.

Normalization happens after the burrs and ensures the different size grinds are dispersed homigenously throughout the puck. Paddles, air puffs, clump busters, dozers all Normalize the grinds.

My first ever post on HB was a partially successful attempt at normalizing grinds on a Mazzer Mini E. Mazzer Mini E - Grind distribution improvement mods

Worked well when it didn't shake itself apart.
Scraping away (slowly) at the tyranny of biases and dogma.

h3yn0w
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#3: Post by h3yn0w »

Seems like a reasonable theory , but IMO 30 seconds to 55 seconds seems a little too extreme to be just due to WDT. I wonder if there is some other variable at play. I would experiment more.

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AssafL
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#4: Post by AssafL »

Well, in the Mazzer Mini E stratification of the puck (towards the rear of the basket - near the handle) meant that the puck only extracted towards the front.

That messed the timing up considerably - and the naked PF showed only 50% extracted.

Definitely not the same situation here - but If the WDT wasnt done correctly it would result in faster pours - not slower.
Scraping away (slowly) at the tyranny of biases and dogma.

mivanitsky
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#5: Post by mivanitsky »

Not surprising at all with a Super Jolly. You may wish to align the burrs. Super Jolly and MiniE are actually very good grinders, if you WDT, and especially if the burrs are well-aligned, which is not necessarily the case from the factory.

No significant difference with any of my three Monoliths, or with Mazzer KonyE or RoburE in my experience, provided that grounds are leveled before tamping, and tamping is level.

This also presumes broken-in burrs. KonyE, which I bought new, was poorly behaved until I put 10kg through it, and absolutely required WDT during that interval. Monoliths were broken in with 5-6kg, and did not require WDT thereafter.

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RapidCoffee
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#6: Post by RapidCoffee »

RockyIII wrote:Is it typical for WDT to cause such a dramatic difference in extraction time? ... Does this mean I am getting a lot more channeling than I think I am, or does it have more to do with the tighter compression?
Yes, this is the likely explanation. Better puck prep helps eliminate channeling. If your non-WDT pucks are channeling, that could easily account for double the flow rate.

But there could be other reasons, including simple measurement error. So I hope you tried this little experiment more than once, making sure that the paired pucks were prepped consistently.
John

Kellyk
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#7: Post by Kellyk »

I'd say you have a lot of retention and the first pull was with 'staler' grounds. I'll bet the third and fourth in a row are the same as the second, but the first pull of the day is much quicker.

brianl
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#8: Post by brianl replying to Kellyk »

IT can also be that the first shot runs with a cold nose and extracts less. Subsequent shots have a warmed up machine.

RockyIII (original poster)
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#9: Post by RockyIII (original poster) »

Kellyk wrote:I'd say you have a lot of retention and the first pull was with 'staler' grounds. I'll bet the third and fourth in a row are the same as the second, but the first pull of the day is much quicker.
I have been purging about 10 grams prior to the first shot. If I do three shots in a row they are all right at or very close to 36 grams in 30 seconds. It has been the most consistent espresso machine I've ever used shot after shot, right up until I tried WDT.

I did a couple more shots. The first one with WDT ran in 49 seconds, and the second one without WDT ran in 28 seconds. Again, after WDT it is noticeable how much lower in the portafilter basket the grounds sink both before and after tamping.

I might try dialing in while using WDT shots to see if they remain consistent at a coarser grind and how the taste is affected. Then I can try a non WDT shot and see if it runs way too fast, which is what I would expect.

The grinder is only a couple of weeks old. Maybe after the burrs are seasoned, things will change. I wonder if a Kony would be acting the same way.

Rocky

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

brianl wrote:IT can also be that the first shot runs with a cold nose and extracts less. Subsequent shots have a warmed up machine.
Here is my procedure before using the Linea Mini:

Add fresh water to reservoir
Turn on machine
Wait 15 minutes for machine to warm up
Flush 150ml of water from the hot water tap
Flush 150ml of water from the group head
Wait 5 minutes
Ready to use

After that, my shots have been consistently the same time and weight until I introduced WDT into the equation.

Rocky

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