Grind consistency of column with weight vs. stock hopper - Page 2

Grinders are one of the keys to exceptional espresso. Discuss them here.
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Peppersass
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#11: Post by Peppersass »

mitch236 wrote:Ian, that was exactly what I was looking for! I'm in the column camp but might have to find a lighter weight!
Having been forced to change the grind of several different grinders as their hoppers emptied, I'm firmly in the camp of either single dosing or using a short weighted column hopper that's replenished after every grind.

But like Jim, I'm a bit skeptical about the short weighted column versus single-dosing with a weight or lid. The argument for the column appears to be that you get consistent pressure on the beans going through the burrs, while with single-dosing you lose all pressure as soon as the weight or lid hits the hopper supports, center screw of the moving burr, etc. But in the case of the column, the weight pressing down on the beans does, in fact vary as you grind the shot: it decreases by the weight of the beans just ground. Now, whether this variation is superior to the variation caused when the weight or lid loses contact with the beans in the single-dosing case is a matter of pure speculation.

My guess: it doesn't matter as long as you adjust the grind accordingly (Jim's assertion about hopper versus single dosing.)

And this leads me to assert that single-dosing is superior because it allows you to switch coffees at any time without waste and you don't have any problems when you have less than a full column of beans left in the bag.

The more important takeaway I get from this thread and the thread on popcorning is that certain coffees may benefit from as light a weight on the bean column as possible. As has been stated, the lighter weight will require a finer grind, which may benefit lightly roasted SOs, similar to the effect postulated by Jim for the finer grind required for VST baskets.

Following Jim's example, I put a single dose in the throat of my K10 and put a Spice Islands jar on top to keep beans from flying out. The jar is filled with peppercorns and I have never opened it (the lid seal is still intact.) I just weighed the jar and it came in at just over 190g. Much heavier than I expected. The label says the net weight of the contents is 2.4 OZ, so getting rid of the peppercorns will reduce the weight by about 67g. Removing the lid will save a few grams, too. I might be able to get the weight down to 100g. Perhaps I can cut the jar in half or less and get it down even lower. Here comes another espresso science project...

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another_jim
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#12: Post by another_jim »

Peppersass wrote:I ... single dose ... my K10 and put a Spice Islands jar on top
I was really hoping somebody would come up with something better looking. It's beginning to look like another exotic wood product for Dave (if he has no ethical objections to single dosing).

On the wider topic. I have single dosed every grinder I've ever had, including the Robur. There are large variations in how much of a PITA it is to do it; but I've never had noticeable differences in the taste or flow consistency of the shots. On the other hand, lots of people whose testimony I've trust have had such differences.

It leaves me scratching my head. For the moment, I don't think experimenting is much use, since I can't think of a hypothesis to test which would explain the differences we are seeing. If we dd have something to test, we could do it, since Sherman has a K10 like mine, and we could set one with a hopper and one for single dosing that produced the same shot dose/flow characteristics.

Mitch appear to like very light, acidic roasts that I mostly find somewhat unbalanced; so one possible hypothesis is that single dosing == hopper for beans and roast profiles common in espresso, but not for the tight rope dancing roasts he likes.

Suggestions?
Jim Schulman

mitch236 (original poster)

#13: Post by mitch236 (original poster) »

(this is in response to Marshall):

I guess what I should have said was I want as close as I can get to rock solid consistency which to me means removing as many variables as possible. Keeping beans in a hopper is a variable. As the hopper empties, the pressure on the grinder throat changes. That's why I'm staying with the column method. My question to the "scientific method" camp was, "Can you taste a difference between column fed beans (with a weight) and hopper fed (keeping bean height consistent)?

I've read the entire thread discussing whether heavy weights affect taste but there seemed to be no conclusion. It would be nice if the weight of the tamper (or whatever device used to weigh down the beans) didn't matter to taste because a heavy weight (within reason) removes the height of the column variable (to a large degree) since the beans themselves contribute very little to the overall column weight seen at the grinder throat.

To Dick and Jim:

I don't understand why I wasn't able to make pure single dosing work. My weight may be the problem however as it is quite heavy and when it hits the auger, all weight is relieved and perhaps this causes too much grind difference?

I will see if Dave will make me a custom weight to fit in my column that weighs as little as possible to test this theory.

To Jim: I think I like highly acidic unbalanced shots because I'm a little unbalanced!!!!

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innermusic

#14: Post by innermusic »

I think the idea is to mimic the weight of a hopper of beans, in which case a tamper is way too heavy. I moved to a half filled plastic pill bottle that fits in the column.
Steve Holt
Trent Hills, Ontario Canada
Vivaldi II, Macap MXK, Baratza Vario

mitch236 (original poster)

#15: Post by mitch236 (original poster) »

This will be my next attempt at making the column work:



https://www.globalindustrial.com/p/moto ... -h1c-100-a

It weighs 60 gm which should be about right for this use

*I edited the post because I linked the wrong collar

mitch236 (original poster)

#16: Post by mitch236 (original poster) »

After some experimentation, it appears that the trouble I've been having can be directly related to the heavy piston I was using to control popcorning. The weight of the piston forcing the beans into the grinder caused the grinds to be finer with the piston than without given the same setting. Because of that, when the beans were being compressed by the weight, the grinds were fine, when the beans fell below the level of the piston the grind suddenly became much coarser causing havoc trying to distribute.

Tonight, I decided to try grinding without anything weighing the beans. After all, the Robur E has an auger which is supposed to help feed beans. Turns out that so far, I am very happy. I was able to acheive good results single dosing. I won't really know how well this works until I have a chance to play with it for a few weeks but so far, so good!

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RapidCoffee
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#17: Post by RapidCoffee »

Presumably the auger helps pulls beans more consistently into the grinding chamber, independent of hopper load. It should significantly reduce popcorning when single dosing. Nonetheless, I suggest you compare single dosing with a column of beans in your minihopper (maintaining at least 75-100g bean load at all times). Let us know which method produces more consistent extractions.
John

mitch236 (original poster)

#18: Post by mitch236 (original poster) » replying to RapidCoffee »

I have no doubt that the column of beans will produce more consistent results. I have proven that already (at least to myself) because as the weight seen by the burr is reduced, the grind drifts coarser. If there were a way to keep the weight absolutely even throughout the grind, that would produce the most consistent grind. To me, the heavier the initial load (within reason, of course) the more consistent the grind because the difference between starting weight and ending weight would be less (as a ratio). Therefore, it would stand to reason that if one were to opt for single dosing, one would want the lowest possible starting weight to keep the start/end ratio as low as possible (realizing that single dosing always has an ending weight of 0 by definition). For me, since my grinder has an auger to help reduce popcorning, that would mean nothing holding down the column. For other grinders, the lightest possible cover would probably be best. Unless you are leaving beans in the column (or grinder throat) at the end of grinding, you would want the lightest starting weight possible while reducing popcorning.

Something like this might work best (shower part)




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RapidCoffee
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#19: Post by RapidCoffee »

mitch236 wrote:To me, the heavier the initial load (within reason, of course) the more consistent the grind because the difference between starting weight and ending weight would be less (as a ratio).
Theoretically, I agree. In practice, a bean load of several double shots in a minihopper appears sufficient for consistent grinding. I experimented with this some time ago, and you can too. Starting with a weighed column of beans (say, 6x17g=102g), grind and dose* one shot after another until the beans are used up, without changing the grind setting. Extract each pour for a fixed time (say, 25s) and weigh the shot. At some point the extraction will begin to flow faster, and the extraction weight will increase. That will give you a rough indication of the bean load required for consistent grinding.

* obviously you need to use a fixed dose weight
John

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innermusic

#20: Post by innermusic »

Starting with a weighed column of beans (say, 6x17g=102g), grind and dose* one shot after another until the beans are used up, without changing the grind setting. Extract each pour for a fixed time (say, 25s) and weigh the shot. At some point the extraction will begin to flow faster, and the extraction weight will increase. That will give you a rough indication of the bean load required for consistent grinding.
Great idea.
Steve Holt
Trent Hills, Ontario Canada
Vivaldi II, Macap MXK, Baratza Vario