Timers on coffee grinders
One of the most important variables in grinding coffee and making espresso is the dose – in other words how many grams of coffee are in the basket. Changing by .5 grams will change the way the shot pulls and tastes.
The first obvious solution is to only put in as much coffee in the grinder as you want to drink, but this has plusses and minuses. Most grinders are not designed to be used this way, so it is not surprising that it is not a perfect solution. See my blog entry on single dosing for more on this.
The next solution is to grind until looking at it, it looks like you have the right amount of coffee. This method has a major flaw in that two identical looking coffee baskets can vary by weight. This is the same issue bakers run into when they try to write a recipe down using cups of flour – a cup just is not a good way to measure flour as it is too inconsistent.
The next solution that suggests itself is using a timer. Many grinders now have digital timers built into them. The Vario is one of the cheaper grinders that has a digital timer in it, and there are lots of other options including huge titans line K30, the Robur E from Mazzer, and the Macap M7D, and plenty of grinders between those two sizes.
A timer seems like a perfect solution, but even this is not perfect (although it is one I really like and often use). A grinder does not tend to give the exact same dose at a given time. The biggest problem is that many espresso blends are far from homogeneous. If the beans are not all exactly the same size (and, of course, even if they are only using one type of bean they will not be the same and if they are using lots of different types it can be dramatic) then the feed rate will vary over time depending on how the beans are distributed within the grinder and the blend.
Most grinders on timers can get within .5 grams, (some are a little better than others and some a little worse) which is not bad but not perfect. If I am in a rush I am happy to trust a timer. If have more time and am in pursuit of perfection I opt for a scale even if I have a timer to be as precise as possible – using the timer to get close and then getting the rest of the way manually.
By the way, you can, of course, add a timer even if your grinder does not have one. There are darkroom timers that can turn the grinder on and off and that go down to .1 seconds that can work for the job (although I have never seen one that is food safe, precise, small, and cheap).
Timers on coffee grinders