Does shipping coffee to hot/humid regions adversely affect quality?

[gadflea]

I have been getting inconsistent results with the coffee I order from a reputable roaster and sponsor of HB. My intent is not to discredit the roaster with this post; I just want to figure out why my espresso from one order will be rich and sweet while the next order is thin and sour.
First, my setup: I temp surf on a silvia and use a bottomless portafilter with the LM ridgeless double basket sold at 1st-line, I dose ~15g of coffee from a rocky grinder and use WDT to break up the clumps, I tamp with a reg barber convex tamper, and I adjust the grind to get ~1 oz in 25-30sec.
The first time I ordered Ecco Reserve, the coffee produced absolutely perfect shots with relatively little fuss. I used my normal routine and the extractions from the bottomless portafilter were thick, gloppy and the resulting espresso was nuanced, sweet and had mouth-filling body. The last two times I have ordered, the extractions have been very thin and watery, prone to pinholes and sputters, and the resulting espresso tastes sour and lacks body and sweetness. I attempt to correct this by tightening the grind until I have choked silvia and then grinding consecutively coarser to find the sweet spot. I just spent most of my evening tweaking my technique to get a better pour from the bag that arrived today. However, each pour has that "thin" characteristic. It seems as if the coffee is old and spent even though the roast date is Jan 31, making it five days old.
Ecco does not use airlock bags to ship their coffee. They send it in a plastic-lined brown paper coffee bag. I live in Houston and I am wondering if the heat and humidity in my area is responsible for the inconsistency and the coffee seeming "spent" even though it is five days old.
I admit that I am probably responsible for the inconsistent results. I have only had Silvia for a year and that is the extent of my experience as a home barista. The problem is that no matter what factors I change (grind, dose, tamp) I can't make the "bad" orders any better. I appreciate any input you guys have.
-Tyler

[HB]

According to a test run by Counter Culture / Intelligentsia, the answer is no. The question came up in Effect of sunlight and summer heat on coffee, excerpted below.

Peter and I were discussing this awhile back; he mentioned that their tests showed no difference between coffees shipped next day air and then stored versus coffees that made the trip by truck. They even tried a few variants, e.g., intentionally storing coffee in the back of a hot truck. Tim (Counter Culture Coffee's head roaster) elaborated a bit in his note:

We did some pretty extensive work on this. Although I agree that coffee needs to be stored in a cool place, I do not think that 30 minutes in a hot truck would make a drastic difference. We left ours in a hot truck for a week and still our triangulation proved to have greater personal difference between coffees that the coffees themselves. (A side note though is that was only 1 test, to give a 100% answer I would want to repeat it many times. )

However the direct sunlight on the coffee jars I do think will kill it pretty quick.

The inconsistencies you report may be a case of Silvia having a "bad espresso day," but I'll defer that diagnosis to current owners.