I recently picked up some new beans from a local roaster. The first day I was able to get some decent pulls after a couple tests. Now, 2 days later, I kept the same grind and dose but am getting extremely sour shots. I tried a finer grind with no noticeable taste difference. Even if I push it to a trickle, it is still coming out too sour to stomach. I switched to a different bean that I have had for a week or so and that one came out fine. My next step is to descale. Anyone have an idea as to why this would be happening?

It could be your water. Could be your taste buds. In the pro world, it would be an extraction issue, so I guess you can check your pucks and development of shot color...

Third wave coffee has always had a perennial identity crisis between sweetness and sourness, which is mediated by quality of the product and your moody taste buds.

Many coffee geeks would frown upon this question, but I'll throw it anyway -- was the coffee meant for espresso or filter?

I told the barista that I was intending it for espresso and he recommended it. The weird part is that I was able to pull good shots from it just a couple days ago. I know it's not my taste buds, my gf tried it as well and thought the same thing. It is overwhelmingly sour. Completely undrinkable. I'm not sure why it is coming out so sour when all the signs point to over extraction if anything.

Give it a coule of days extra and try again, I recently started roasting and fimd that some roasts rally need a five day rest before becoming palatable and frequently they are just great once fully rested...

Hello and welcome!

I have great news! The solution to your problem is three posts below yours, in this very forum!

Slow and Sour Pull

And, parenthetically, there is one additional fact that you've shared that tells everyone success is just around the corner. If you've had a good shot from these very beans, then we can conclusively rule out that your brew head temperature is too cold. This is fantastic news since it's one less variable that you might need to fiddle with.

From my chair, the really profound fact about coffee espresso is that brew head temps align with e=mc2 so neatly. Let me explain.

(please excuse my lack of formulae expression here, but maybe that's ok?), but it is equally true that:

Brewhead temp:
sour = too cold, and bitter = too hot

But, since you've experienced tastiness the previous post applies. We know your brew head temps are in the ball park!

Grind more beans and report back!

jwCrema wrote:And, parenthetically, there is one additional fact that you've shared that tells everyone success is just around the corner. If you've had a good shot from these very beans, then we can conclusively rule out that your brew head temperature is too cold.

This is the part that confused me. Since I had pulled good shots with these beans then turned around 2 days later and couldn't replicate it with the same settings, I don't know what could be going wrong. With all of the other beans I have tried, these are the first that I have had a problem replicating results with. I am still fairly new to home espresso but I do understand the relationship between grind and taste. For some reason these beans aren't following those guidelines in any way. I can grind finer and up the dose and come out with a shot just as sour. It is to the point that I get largely less volume extracted because the grind is so tight. I will try again tomorrow and see if the results are different.

This really is a journey - and a science project. Just change one thing at a time so "you know" - your taste buds will tell you when you've arrived. The trick is being consistent, which I think is only possible by knowing your measurements and process.

I think you're close....

Well I went through the whole bag, no good pulls. Changing one thing at a time gave me almost identical results; Bright, sour shots every time no matter the grind or dose. I will be avoiding that company from now on... even though it's probably not their fault and I must be missing something.

While I don't work for any coffee company, Redbird Espresso from RedBird Coffee is a known good roaster I'd recommend to narrow the list of possible issues.

http://redbirdcoffee.com/

I learned about them from HB.Com and have enjoyed it for a while. Very consistent quality from bag to bag. I buy the 5 lb versions, but I'd do a 1 lb bag to start with. I also open the bag and let it sit for a week before I use it - the flavor is better.