Does elevation have an effect on the taste of beer?

According to some quick research there is published evidence that our taste changes with altitude (http://www.ncbi.nlm.nih.gov/pubmed/5021819). Interestingly the amount of bitternenss that was tolerable increases signficantly at 5,000 feet (but doesn't increase beyond that when at 10,000 feet). The effect on sweetness was not altered significantly. What that means is that basically at higher altitude our perception of bitterness is turned down, and so potentially other flavors could become dominant. Thus at the 3,000 feet you might have observed a reduction in bitterness due to altitude and become more aware of the unfermented sugars due to this reduced perceived bitterness.

That is pretty neat. I grew up at 7,000 and next time I am at my parents I will have to see if a Stone Ruination tastes less bitter than where I live at sea level.

Airlines routinely select their wines and foods to account for taste differences during flight, nothing that they taste typically less sweet in the air, although this is more to do with the in-flight conditions - pressurized climate, dry air dehydrating passengers, harsh light, engine noise etc, all go to affect the perceived taste of the wine and food.

In your case, going from 300 to 3000 feet in itself doesn't make any significant difference to the beer itself, but you may perceive it differently, especially if you're not used to being at that altitude.

It could be in part that you were just being more critical since you were tasting in front of family/friends. Taste can very from day to day according to many factors such as how you're feeling, your state of health and what you've previously eaten and drank that day.

But having said that, your perception that the beer was sweeter ties in with practices for high altitude cooking (3000ft and over.)

Sugar adjustments: Although I really don't understand why, I do know that I often have to reduce sugar in some recipes. For high altitude cooking, this guideline really does work to make cakes and cookies taste better: for every cup of sugar you'd normally use, reduce that by 1 tablespoon at around 3,000 feet to as much as 3 tablespoons less at even higher altitudes. It does make a difference in the taste of your final product!

So you may have to start making the beers a little more fermentable to reduce the overall sweetness if you're planning on drinking them over at your parent's place, or have them come to you instead and see if the beer is the more in line with how you expect it to taste.

Yep, it seems it does affect it. You will get lower carbonation at higher elevation and also the boil temperature is lower in higher elevation.

See a forum post and communication on HomeBrewTalk: http://www.homebrewtalk.com/f35/effects-altitude-carbonation-1523/

"The other issue is when you drink the beer. Since you are at altitude when you open and drink the beer, it will tend to lose its carbonation faster because of the lower atmospheric pressure, so you may perceive more carbonation.

What does it all mean? It means, if you bottle and drink at the same elevation, the same amount of priming sugar will produce the same amount of CO2 and the same perceived carbonation level. Now: what happens when you bottle at elevation and take it down to sea level and vice versa? Lower levels of perceived carbonation for the bottled high and drunk low beer, and higher levels of perceived carbonation for the bottled low and drunk high beer."