Coffee – Domestic, fresh taste-alike for an Italian coffee

Posted as answer by request of @BaffledCook:

Here's an slightly informal blog post outlining changes in taste between varying degrees of freshness in the grind of a coffee.

http://investigationsblog.wordpress.com/2010/03/03/do-i-really-have-to-grind-coffee-right-before-brewing-it/

The short version is that the coffee starts losing freshness as soon as it is ROASTED. The longer it sits the faster it goes stale. The more surface area it has (ie: you've ground it up; also, the finer the grind), the faster it goes stale. The more you expose it to air, the faster it goes stale. So, seal your coffee in an air tight container at room temperature. And grind as close to the time you add water to it as possible.

How much of a difference detected depends on the the actual coffee been, the roast, the taster's taste buds. If you buy a bean that's been sitting on the shelf for 3 months already, you will probably notice less of a difference than a bean that was roasted last week. I buy beans that are roasted and sold within a week, and I DO notice a difference if I leave the grounds for a day or two before drinking.

One possible difference is that when you pour coffee (or any other hot liquid) into a ceramic mug, the liquid cools a fair bit (the heat is "lost" to heating the ceramic cup). The double-walled stainless mug is designed to lose as little heat as possible, and the inner wall has much less thermal mass than the ceramic. So, when you pour the creamer into the stainless cup, the coffee is hotter.

The simplest way to test if this is the case, would be to measure with an accurate thermometer. And the solution, then, would be to allow the coffee to cool some before adding the creamer.

Alternatively, temper in the creamer. To do this, put the creamer in the cup first, then add a little coffee, stir, add a little more coffee, stir, then add the rest. The idea is to slowly heat the creamer up to the coffee's temperature. This should prevent curdling, even if your coffee is near-boiling.

It could be some residue on the cup, but I doubt it, because stainless is fairly easy to clean. Also, it'd be hard to imagine enough residue to curdle the cream without also being very evident in the taste of the coffee. Stainless steel itself is pretty non-reactive, so its probably not a reaction with the coffee or cream.