Is single dose [without hopper] grinding inconsistent? - Page 3

[Teme]

I am adding the detailed scores that I'm keeping for later analysis at Teme's request. Teme is not one of the grinder testers, since shipping the grinders to Copenhagen is somewhat awkward. He is, however, one of the heavy hitters when it comes to this whole review process. He has done exemplary work testing a whole set of grinders there, including publishing and interpreting the first ever enthusiast generated particle size comparisons among top grinders. Dan and the rest of us are eager for any input he might give to the final article. If he wants to see the detailed data, he gets it.

I raise my hat to everyone who has participated to TGP, especially Jim (and including the sponsors). The project, including the comparisons and scoring of the grinders against the Robur is an invaluable resource and reference for many.

Thanks for the kind words. I personally feel that the limited testing I did on a few grinders could have been of more use if I had had more time, resources and counter space available

I will need to take some time now to digest all the information on the posts that the TGP has spawned, but I would be more than happy to contribute to the final article if you'd like.

FWIW, I had a chance to play around with the Conti Valerio MDM Conical (branded as LM) and I quite liked it (except for the fact that the grinder kept jamming on me - a faulty unit or an underpowered motor?). I had no grinder to compare it to in terms of taste so unfortunately no comment here other than that it produced a very good cup. I did not like the grind fineness adjustment much, though and it seemed fairly sensitive to the fineness setting. The doser was very good - it swept clean and dropped the grounds straight down into the PF no matter how hard one "thwacked".

As for the poll of this thread, I usually keep a small amount of beans in the (chopped) hopper to put some weight on the ones being ground. I clean the doser and chute with a brush after each session, but there's naturally some (ground and partially ground) coffee left in the grinding chamber. I therefore throw away the first few grams at the beginning of each session. I, too have noted that the shots ground with less weight on the beans do run faster, which can to some extent be compensated for by dosing a bit more. I do not see staleness as an issue as the beans are freshly roasted (I prefer 4-10 days from roast date) and they do not stay in the hopper for long (24 hours max).

Br,
Teme

[Ken Fox]

That's the whole story in a nutshell -- "Single portion grinding with a doser - 101"

One reason I go hopperless is that using a hopper and sacrificial grinding entails around 4 to 5 grams waste per shot. Since I home roast, any time saving on grinding will be more than eaten up by the extra roasting time.

There are two issues here, and in my opinion, they are unrelated.

I raised the issue that resulted in this thread initially because I was (and remain) concerned about the effect on the grinds when the hopper is run empty, with no weight on top of the beans as they are entering the burrs. At the least, this changes the grind, probably to a different extent in each grinder, as evidenced by the faster pours that some have noted result from this practice. This could also change the grind CHARACTER, e.g. distribution of particle sizes, however this is undocumented. If the latter were true, then comparing two grinders run empty might result in different conclusions about those same two grinders, were they run with at least some beans in some sort of hopper.

The other issue is coffee waste when large commercial type grinders are used in a home or other low volume setting. In order to avoid using previously ground, "stale," grinds, one has various options. I like the option of cleaning out the chute with each shot, and using those grinds if need be; that makes perfect sense, keeps the grinder clean, and does not effect the grind. I think it makes more sense to pulse the grinder for a second before making the NEXT shot, as a way to clean out the doser, so I see no benefit in this regard with running an empty hopper.

On the other hand, putting just enough beans into the grinder as are needed for the shot, will probably result in a variation in the grind quality in the grinds that are being used for that shot. The first part will grind as if there was a bean "column" on top and the second will not. Whatever sort of weight (tamper, spice jar, what-have-you), will not put uniform downward pressure on the beans being ground at the end. The camshaft of the top burr will not allow this, so the last few grams of coffee will probably grind more coarsely, if my interpretation of "faster pours" resulting is correct. So, you will get a mixture of beans ground one way with beans ground another.

Will this be tastable? I have no idea.

Still, for my money, these grinders should be evaluated in as close to a stock configuration as possible, and then the readers can decide to what extent they want to deviate from this. But, evaluations based on usage with empty hoppers or no bean load above, are going to produce results that probably vary from what a buyer using a grinder as it was designed, will get.

If I'm the only one here who sees a problem with that, then so be it.

ken

[jesawdy]

If I'm the only one here who sees a problem with that, then so be it.

Well, Ken, we're getting pummeled in the poll above, although not as bad as those that keep some beans in the hopper once were. It looks as though Jim's no hopper/mini-hopper use is right on with a number of home baristas.

I hope to try keeping a smaller amount of beans in the hopper weighted with something above, a thin bag of dried beans, a bag of rice, whatever might approximate the bean weight without having kilos of coffee beans in the hopper at a time.

[Ken Fox]

Well, Ken, we're getting pummeled in the poll above, although not as bad as those that keep some beans in the hopper once were. It looks as though Jim's no hopper/mini-hopper use is right on with a number of home baristas.

I hope to try keeping a smaller amount of beans in the hopper weighted with something above, a thin bag of dried beans, a bag of rice, whatever might approximate the bean weight without having kilos of coffee beans in the hopper at a time.

Jeff,

Most people think that "farmed salmon" is edible, too.

Don't ever challenge other people to a race to the bottom. because if you have any taste, I can promise that you will lose.

I'm not advocating putting a kilogram of beans in there to weigh things down, but I do think that a few ounces are a good idea. My own observation is that when the hopper is almost empty, the last shot tends to suck, no matter what I do with the grind setting.

Just my opinion.

ken

[cafeIKE]

My own observation is that when the hopper is almost empty, the last shot tends to

be inconsistent

, no matter what I do with the grind setting.

[DavidMLewis]

I certainly understand that these grinders weren't designed for this kind of service and may not perform optimally when used that way. But as an engineer, I think it's important not to confuse how we have to use existing artifacts with how we'd like to be able to use them. As a home user, I'd like something relatively small that would allow me to change coffees and brew methods throughout the day with minimal waste or carry-over. It's not clear to me that such a thing couldn't be designed, particularly at the price point we're starting to talk about. I never got an answer to the question about how the M3 does it, given that it was designed for this kind of service: do the last few beans popcorn, or is the augur designed to prevent this somehow? Could one, for instance, take a 3-phase Robur burr set and rotate it more slowly, given that in the home grinding time isn't as critical as it is in a busy cafe, and not have it popcorn? I suspect John Ermacoff may have the answer to that one.

Best,
David

[another_jim]

I never got an answer to the question about how the M3 does it, given that it was designed for this kind of service: do the last few beans popcorn, or is the augur designed to prevent this somehow?

It popcorns throughout the grind, but a baffle prevents the beans (mostly) from jumping out. The M3 takes about 20 seconds to do a double, versus the 12 of a mini, 8 or so for the Max or Jolly, and 5 seconds of the big conicals. The slower grind means a slower feed, and less popcorning than from the commercial grinders.

Even on a manual grinder, the beans sometimes don't get grabbed by the burr entrance and pop out. The low rotation speed just means they don't go very far.

There certainly is a change in the grind setting between grinding a single dose and from a full hopper. However, the taste doesn't seem to change. I wouldn't be at all surprised if it turns out to be a non-issue, and the grind is not physically different either. There is some play in these grinders -- the threading of burrs, bearings, gears, etc. It could simply be that when the feed rate changes, and the amount of beans being ground at once also changes, the burr gap changes as well.

[Ken Fox]

I certainly understand that these grinders weren't designed for this kind of service and may not perform optimally when used that way. But as an engineer, I think it's important not to confuse how we have to use existing artifacts with how we'd like to be able to use them. As a home user, I'd like something relatively small that would allow me to change coffees and brew methods throughout the day with minimal waste or carry-over. It's not clear to me that such a thing couldn't be designed, particularly at the price point we're starting to talk about. I never got an answer to the question about how the M3 does it, given that it was designed for this kind of service: do the last few beans popcorn, or is the augur designed to prevent this somehow? Could one, for instance, take a 3-phase Robur burr set and rotate it more slowly, given that in the home grinding time isn't as critical as it is in a busy cafe, and not have it popcorn? I suspect John Ermacoff may have the answer to that one.

Best,
David

Given the fact that LM thinks there is a big enough market to serve with an espresso machine like the GS3, and the fact that the potential market for an ultra high end home grinder must be many times larger, I'd be surprised if one of the mfrs. doesn't eventually decide that this is a market niche worth serving.

ken

[HB]

Given the fact that LM thinks there is a big enough market to serve with an espresso machine like the GS3...

You assume La Marzocco will make money on the GS3. Given their high cost support structure, (relatively) low retail price compared to the model's complexity, and low production, I wonder if that's true. La Marzocco lost a huge client and unbounded visibility when Starbucks went super-auto. Sometimes I think the GS3 is a loss leader. What other La Marzocco product has been relentless bantered about the Internet and among "third wave" baristas for three years running while barely in production? Good market exposure is worth sacrificing a bit of profit on a mere 140 units per year.