Ken Fox wrote:I have a question for Jim and anyone else who lives in an area where the relative humidity changes frequently and by large percentages (like 25% in a day).

Here's the question: If you have a really good grinder (say a "Titan," either a large conical or a Max hybrid planar/conical) and if you take the peak period for a given coffee, which for me tends to be during the period between days 3 and days 8 after roasting . . . . . even with the changes in humidity which might occur during this "prime" period -- do you still have to change your grind settings much???

Variations between 65-95% are relatively common. Elektra Nino. Generally whenever I move the grind, its to my detriment. Now I have a vivid mark and seldom adjust it from there. If I do, thats why the mark is there, as I constantly find my way back to where I started...

We usually have the aircon on, that may stabilise the RH inside however.

Yesterday, 090910, humidity varied from 95% @07:00 to 13% @ 14:00.
http://data.piercecollege.edu/weather/l ... quinth.htm

Grinder changes : 0

Unless pulling back to back shots, tweaking the grind based on a grinder that's going to sit for a few hours is like deciding to turn on the windscreen wipers because it's raining in the next county.

why tweak the grind on back to back pulls?

SOP here is a single every cupla hours. Back to back when tweaking a new roast.

Fantastic topic; I've been experimenting with a single origin Rwanda that I want to "tone down" and this has helped quite a bit.

You guys lost me back with quarters, nickels, holes, linear stuff. I'm just a computer guy that likes a good cup of coffee or espresso.

Skipping over two pages of math my take away is this. For those of us with entry level kit, specifically grinders like the Gaggia MDF stepped grinder. Once you hit the sweet spot, adjust your dose to vary your extraction rate when...

1.The adjustment on my stepped grinder causes a wider swing in grind and subsequent shot timing than is needed based on the current flow rate.

2.The change in dose does not cause a dramatic shift in flavor. If it does have a negative impact, then adjust the grind instead.

3.My non stepped grinder is experiencing a shift in extraction rate based on environmental variables that may be reversed the next day. Instead of chasing the grind and purging out a few ounces of coffee every time I make a minute change, just dose a little more today, a little less tomorrow. That will avoid the grinder fiddling and wasted coffee.

4.Slight variations in dose do not cause undesirable effects in the cup.

I wish I had my gear to experiment around with this. Moving sucks, having your espresso machine in storage for 4 months sucks even worse.

After spending a month taking a few blends and SOs out from fresh to around twenty days old, I'm getting more extreme in my impression. As the coffee gets older, grind coarser and really updose to counteract the faster flow. This is the only way to keep the taste balance fairly constant.

As properly stored, non-oxidizing coffee ages, the primary effect is the loss of volatiles through evaporation and of unstable compounds through chemical reactions. These are typically lighter molecular weight compounds that dissolve quickly, so that they get into the cup earlier in the extraction. As their proportion in the unbrewed coffee drops, one wants to lower the solids extraction during brewing in order to reduce the amount of slow dissolving compounds in the cup as well. This maintains the taste balance. Hence coarsening the grind and using much higher dose is probably the best bet for retaining the most consistent taste as the coffee ages.

I'm wondering if there is a correlation in commercial blends between their resting and dosing recommendations, so that longer rests go with to higher doses?

OMG. Is this another one of those rare, rare instances where Jim and Chris Tacy actually AGREE (at least somewhat)?

another_jim wrote:As the coffee gets older, grind coarser and really updose to counteract the faster flow. This is the only way to keep the taste balance fairly constant.

chris tacy wrote:With a triple basket you can get decent shots with stale coffee. (This is the important one. Today I experimented with some 7 day old coffee from Ecco Caffe. When fresh, this was a lovely, subtle and balanced espresso. Now, in a double basket it is quite flat and undefined, with little dynamic range and limited aromatics. In the triple basket, however, I can pull a 1.75oz shot that is incredibly concentrated, dense and enjoyable - especially in milk. My guess is that I should be able to get decent shots out of this coffee this way for another day or two.)

As I wrote Jim in an email yesterday, my own observations are that by increasing dose as a coffee stales, you can improve the resulting drinks over what you would have gotten with that stale coffee had you left the dose constant. However, and it is a very big however, the resulting drinks are still inferior to the lower dosed drinks that I get with the same coffee when it is fresh. To me this argues more for limiting the amount of coffee that I leave out at any given time, freezing the rest for later use, than it argues for trying to get more out of past-prime coffee by altering dose and grind.

ken

AndyS wrote:OMG. Is this another one of those rare, rare instances where Jim and Chris Tacy actually AGREE (at least somewhat)?

I wonder if that means were almost certainly right or almost certainly wrong.