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a (not so) quick experiment - single dosed grinders


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I've done a (pretty) quick experiment today with surprising results, maybe someone else can try the following as well and report back? All you need is a flat / conical grinder which allows single dosing and three cups marked A, B, C.

 

1. Measure out your standard dose, lets assume this is 18g, drop that into the burr chamber, no beans on top, no weights, tampers etc.

 

2. Now this might be tricky on fast grinders, turn the grinder on for a brief moment so that it only grinds 6g, drop that dose in a cup A.

 

3. Do another 6g dose and drop that in cup B

 

4. Grind the remainder (should be close to 6g) and drop that in cup C.

 

5. Repeat points 1 - 4 two more times, so that you end up with roughly 18g in each of the A, B, C cups.

 

Pull shots with each of the cup doses and observe what happens. Do they all flow / extract the same, or is it all different?

 

Report back:)

 

Cheers,

T.

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That's the main problem with this experiment I'm afraid, it's only really suited for slow grinders. Besides the EK probably isn't affected by bean weight issues anyway.

 

T.

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Just so I understand, you will end up with 3 cups;

 

Cup A will be full of grounds ground in the first part of the cycle, where there was circa. 12g of beans behind them in the hopper, including the initial 'uptake' (I believe @garydyke1 has mentioned about this before when he advised against single dosing a Royal?)

Cup B will have the mid-cycle, beans already in the burrs, beans behind the ones being ground.

Cup C will have the end of the cycle, nothing behind the beans to push them through

 

If you want I can repeat with weight on top, or is that stage 2?

Edited by risky
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Damn that's a massive difference in shot speed! what grinder is this on?

 

Basically what you've done is shown how the grind size or grind shape changes over the course of a single dose grind. The first shot which was a choker was made out of the first 6g of each of the three grinds. This was with 12g of beans above the 6g being ground, so with some weight behind the beans, probably no popcorning either. This produced the finest grind or the most amount of fines, enough to slow the shot well over 1min. The 'middle' bit, so the 'second' 6g was produced with just a bit of beans above (only 6g left at the end of this stage), came out coarser, or more "chopped"? Then came the last 6g, no weight above the dose being ground, probably heavy popcorning, loads of "shards" in the grind I'm guessing and perhaps no fines what so ever (or maybe the same amount as at the very beginning, but I'm guessing the shape of the rest of the beans was different)? All of this resulted in a gusher.

 

The above shows that during single dosing the grind is massively inconsistent, you get some 'normal' grinds, some slightly coarser and some proper rocks / shards which probably cock everything up. Yes altogether it works, but it's a bit like mixing different grind levels on a normal hopper fed grinder.

 

That is my take on it anyways :)

 

T.

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Cup A - 18g > 35g > 1m12s

Cup B - 18g > 35g > 18s

Cup C - 18g > 35g > 8s

 

So there we are. Quite startling. No idea if this helps you at all.

Just as a reference, if you grind all in one go what's the shot time and also what's the shot time with a weight on the beans?

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Right I will repeat tomorrow night if I get a chance as this morning I noticed that the burrs were chirping at a far courser setting that usual. Opened the grinder up after this and cleaned out the burrs and the chirp point moved much finer.

 

@Xpenno I did want to try that but for the above reason it wasn't possible, however I do have a note from my previous experiments when I made my dosing device that time without the weight on was almost exactly double that with no weight. Quite a considerable adjustment in the grind setting was needed. Basically gave you a lot more room to adjust your grind as with weight you had to set the grinder a lot courser.

 

@dsc Grinder is a Super Jolly, new steel burrs, probably less than 3kgs through them.

 

@urbanbumpkin you might be surprised, I was. I've never switched the grinder off mid-grind but of course the beans in the burrs causes the burrs to stop spinning almost immediately when the motor shuts off. I found I could pulse the grinder and get 0.5g out per time pretty much.

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Right I will repeat tomorrow night if I get a chance as this morning I noticed that the burrs were chirping at a far courser setting that usual. Opened the grinder up after this and cleaned out the burrs and the chirp point moved much finer.

 

@Xpenno I did want to try that but for the above reason it wasn't possible, however I do have a note from my previous experiments when I made my dosing device that time without the weight on was almost exactly double that with no weight. Quite a considerable adjustment in the grind setting was needed. Basically gave you a lot more room to adjust your grind as with weight you had to set the grinder a lot courser.

 

@dsc Grinder is a Super Jolly, new steel burrs, probably less than 3kgs through them.

 

@urbanbumpkin you might be surprised, I was. I've never switched the grinder off mid-grind but of course the beans in the burrs causes the burrs to stop spinning almost immediately when the motor shuts off. I found I could pulse the grinder and get 0.5g out per time pretty much.

Cool, I was more interested in comparing the whole unweighed shot to the 3 split shots. This would tell us a little bit about where the standard single dose sits within the comparison of the three I.e. is it 15s or 45s?

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I'll try that tomorrow.

 

From previous notes, no weight on beans full shot resulted in a 12 second shot, compared to 24 seconds for weighted, that was 17g>35g, however the grind setting would have been different.

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I'll try that tomorrow.

 

From previous notes, no weight on beans full shot resulted in a 12 second shot, compared to 24 seconds for weighted, that was 17g>35g, however the grind setting would have been different.

 

Nice one, sorry for being a pain, the EK grinds 20g in about 2 seconds so it's not really an option for me to test :)

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Out of interest @dsc have you approached Socratic Coffee about maybe doing an experiment along these lines? I know they are just doing one at the moment about the effect of new vs. old burrs on the grind.

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Out of interest @dsc have you approached Socratic Coffee about maybe doing an experiment along these lines? I know they are just doing one at the moment about the effect of new vs. old burrs on the grind.

 

Had no idea they are doing something like this, might give them a shout, although I won't be home for the next week and a half, so wouldn't be able to participate in anything (of course they could try it themselves and report back).

 

My results are quite different, I've done some testing yesterday but had to add more freezed beans to the last shot as I ran out, so I thought I'd re-do it with the same batch for all three cups. Yesterday I managed to hit the weight distribution better, today I cocked up a bit and got the following:

 

A: 18.2g in - 37.2g out in 32sec - 9.1%TDS which gives 19.38% extraction

B: 19.0g in - 36.9g out in 34sec - 9.5% TDS which gives 19.22% extraction

C: 16.5g in - 36.8g out in 24sec - 8.0% TDS which gives 18.59% extraction

 

As you can see extraction rate is fairly good, all shots where sort of in the middle of either Normale or Lungo on the VST software. Taste wise I wasn't impressed with any of them, but I was tasting this when it was all cold, so that might've had an effect. I'm also not sure the burrs I'm using are seasoned all the way, so this might not be perfect.

 

One thing to mention which I forgot before is to thoroughly mix the 3 x 6g doses before you throw everything in the basket.

 

T.

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That is interesting. I would have expected some change (though not as much as risky observed!). So, I had to try this myself

 

A: 18->36 37sec

B: 18->36 40sec

C: 18->36.2 26sec

(I seem to be getting the hang of these brewista scales ...)

Without splitting: 18->36.4 26sec (which is the interesting bit)

 

I ground a slightly more than 18g each time, and reduced each 3x6ish dose to exactly 18g.

 

This was using a 68mm conical.

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