Issues with grinding my own beans

Question

I currently use a Delinghi Espresso machine and have always bought ready ground coffee because the cost of a decent grinder is quite high. However for Christmas this year, quite a few people bought me coffee beans so I decided to buy myself (what I thought to be) a good budget grinder - Melitta Molino (Melitta seem to have a good name when it comes to coffee particularly when talking about filter coffee)

My question is... I have been using the Lavazza Espresso beans and generally grind about 10 cups worth at a time. I notice that on the day of grinding the water basically runs straight through, there is next to no, dark syrup colour, it tends to start mid brown and within seconds looks clear.

the next day, however, I get a great coffee, nice dark syrup to begin which gets gradually lighter

I have used other beans which are generally darker, the lavazza Espresso beans are quite light in colour, I have not noticed this issue with other beans but I'm not sure if that is simply because they are more intense.

Should coffee brew better a day after grinding? does it let the ground beans dry out or something? Or is it something that might be specific to these particular beans?

Or might there be something else that is causing the issue?

Answer 1

Reviews of the Melitta Molino indicate that the unit is not actually capable of achieving the very fine grind needed for espresso. Sorry to be the bearer of bad news.

Espresso grinders require very tight tolerances in manufacturing to enable the close proximity of burrs required for very fine grinding. This is why the vast majority of grinders made by reputable companies and advertised as "for espresso" tend to start in the several hundreds of dollars range. There's unfortunately no way to shortcut this requirement; loose tolerances would result in too many units being returned when burrs lock up from touching or people complaining that the grind isn't consistent enough. You might sometimes get decent results from cheap grinders, but cheaper grinders will lack consistency and may not be able to achieve very fine grinds at all with some beans.

Unfortunately the cheapest grinder I would recommend for espresso is the Eureka Mignon Filtro, which is generally priced in the US at $210. Also, the vast majority of grinders that grind well for espresso cannot grind well at coarser grind settings, so you'll likely want a separate grinder if you use other brew methods. Your Melitta should be ok for Aeropress, drip, and maybe French Press (not sure at that level of coarseness), so it's not a waste.

Regarding coffee tasting better a day after grinding, this might have to do with the coffee itself. Roasted coffee retains some natural gasses that are created when the coffee is roasted. These gasses slowly seep out as the coffee "rests" after roasting. When coffee is left as whole bean, this process can take quite a long time due to the small surface area of exposed bean. After grinding, the process is expedited a lot as a result of (much) more bean surface area being exposed. If you're sensitive to the flavors of these gasses or if you're buying freshly roasted coffee, this degassing process might explain the flavor difference. This would also explain why water seems to run right through the beans on the first day but not on the second: the gasses are highly soluble in water. The "fast flow" problem is frequently observed among coffee roasters when the coffee is too fresh.

Answer 2

I read a review for the Melitta Molino and one of the Cons listed in the review said "Grind not uniform enough"

Any burr coffee grinder that does not give a consistent grind is useless, as all brewing methods are dependent on a consistent grind to produce a quality tasting cup of coffee.

Whatever grinder you use it should be able to grind the beans to the correct size for the brewing method you are using.

Should coffee brew better a day after grinding?

NO, The reason we grind at the time of brewing is because it gives the freshest and best quality cup of coffee.

Answer 3

I wonder if this has to do with the water content of the bean. Perhaps your beans are particularly dry when first ground. Then after several hours / days, the grounds absorb water from the atmosphere. Have you ever noticed very dry powders allow water to bead up? This is because very dry material is hydrophobic (water repelling).

Some espresso makers will give the fresh grounds a tiny bit of hot water followed by a delay and then the full shot. This delay, I think, moistens the grounds. If your espresso maker has no such delay, try moistening the fresh grounds yourself before getting a shot.

Certainly the answers regarding grinder quality and grinding ahead of time have merit, but the OP obtains "good coffee" using the same, apparently mediocre, grinder when the grounds are >one day old. Grinder type does not explain this observation.