by Peppersass on Thu Dec 08, 2011 4:46 pm Marshall wrote:If you can't see a 2g. difference by looking at the tamped coffee in your portafilter, you are only looking, but not "seeing.".
What evidence do you have for such an assertion? You're assuming that it's possible for anyone to accurately dose by eye, but don't provide any proof of that. Sounds like an unsubstantiated opinion to me.
Marshall wrote:Try training yourself to really see how high from the lip the tamper settles or how deep from the lip the coffee puck sits when you have a dose that tastes right to you.
This is a highly subjective test that assumes the weight of the dose always matches the level of the grounds in the basket, and that the level can be accurately determined by eye. You've provided no evidence to that effect. As suggested by others, the correct test is to use a .1g scale to check what you dose by eye. That will tell you how accurately you can dose by eye. Once you know the amount of variation, use the scale to dose at the extremes of your accuracy and see if you can taste the difference. Allow enough time between shots for your palette to recover.
Marshall wrote:For what it's worth, my rarely-weighed doses are typically 19g in a VST double basket. But for me this is useless information that only comes up after the fact, when I have adjusted time and grind to taste. This would be 6 ticks above zero and 11 seconds on my ProM for the Paradise Espresso Nuevo I am drinking this week. Of course, if your grinder and timer are reliable, time becomes an analog for weight. But dosing by time has the huge advantages over dosing by weight of (1) not having to measure the dose for each shot (the timer automatically repeats the dose) and (2) not having to single dose..
Ah. Now you've changed the assertion from "everyone can learn to accurately dose by eye" to "timed grinding is as accurate as weighing." So now we find out that you don't rely on the level of the coffee in the basket. You've made quite a fuss about a technique you don't even use.
Sure, timed dosing has the potential to be more accurate than eyeballing the dose. But there are factors that can affect the accuracy of timed dosing, including the roast batch, days past roast, level of beans in the hopper and amibient humidity. I used your Pro-M's little cousin, the Baratza Vario, for many months and found that the dose was fairly consistent most of the time, but not always. Sometimes a little coffee would get hung up in the chute and come out with the next grind. I also noticed a variation in the dose weight between the hopper being full of beans and being a few shots away from empty. As a result of these variations, the dose could be off by 1g-2g. That's enough to chage the flow rate, and the combination of more coffee and a different flow rate would distinctly change the taste of the shot. When I started weighing the dose from the Vario, my shots became more consistent (as long as I kept enough beans in the hopper.)
Marshall wrote:Now, I've been called out several times in this thread for blindly applying professional coffee shop standard to home practices. But, I actually think it is the misplaced worship of commercial grinding equipment, specifically the giant conicals, that has created the perceived need for weighing and single dosing rituals. Those machines are simply too fast to accurately dose by time.
I've not seen any reports that large conical grinders are too fast for timed dosing that's as accurate as smaller grinders. There are timed versions of the K10 and the Robur, and some home baristas have added timers to the dosered versions.
Rotations speed certainly has nothing to do with it. My K10 WBC rotates at 325 RPM and the Robur rotates at 300 RPM. Your Pro-M rotates at 1650-1850 RPM. Now, it may be true that the larger burrs/chamber in the big grinders results in faster grind times than your Pro-M, but if burr chamber size is a factor in grind speed, and therefore timed accuracy, the Vario ought to be more accurate than I found it to be.
I suspect that if there's any problem with timers on large grinders, it has more to do with grind retention in the burr chamber and chute than grind speed. This suggests that grinders with a non-vertical chute of any size may be subject to retention that affects the accurace of timed dosing. Perhaps the only exeption would be the Versalab, which has no timer. Note that the retention factor can be reduced or eliminated by single dosing.
But even if Titan conicals are too fast for timed dosing, to me the advantages in grind quality and consistency are well worth the minor requirement to weigh each dose.
I think it's very interesting that Baratza eliminated the timer in the new Vario-W. It doses entirely by target weight. I would guess that the grinder was developed in response to customer demand (something you might consider), but it's also an acknowledgement that weighing is a valid approach. It's true that you have to dose into the grinds collector and then dump the contents into the PF, but that takes hardly any time or effort and can actually be less messy. Surely this is the future of espresso grinders. Once scales are built into grinders and espresso machines, your arguments against them will disappear.
You've also mischaracterized the "perceived need for weighing and single dosing rituals" (note the pejorative use of the word ritual.)
As previously stated, weighing the dose is an attempt to control one of the key variables in the extraction process. Some of us find this to be easier and more accurately done with a .1g scale than by eye or by using a timer. It's no a big deal for a home-barista, and many of us have found it to have greatly improved the consistency of our shots.
There are a number of reasons for single dosing, but dose accuracy isn't one of them, nor is the use of a large professional grinder. I don't single dose because I have a K10 WBC. I chose the K10 is because it works well for single dosing. I single dose because I like to change coffees frequently, like to keep the burr chamber and grinder chute free from stale grinds, and I prefer to waste as little coffee as possible. Also, I find grind consistency is improved when the variation in hopper level is eliminated (a problem for every espresso grinder on the market.) Yes, it does require a bit more effort, but it's worth it to me for my daily espresso preparation. But you can be sure that if I had a party of 15 people here demanding coffee drinks, I'd bring out the hopper. I would keep the beans at a constant level and I would weigh every dose. The weighing "ritual" would add all of 3-5 seconds to the preparation of each shot.
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