I need help to solve a mystery. Im a a newbie to the espresso scene, but live in NYC where great coffee shops are plentiful, so I know what a good espresso should taste like. And with my bdb 920xl and Baratza Vario grinder I can make a consistently great espresso/cappuccino lately .... But with one caveat. The first espresso that I make is great. But every consecutive one is sour. I am dosing coffee and output consistently, and tamping consistently and extractions are consistent in terms of flow and time.

As far as I can guess, it has to be either the grinder does something different on consecutive grinds, perhaps due to hotter burrs..... Or my bdb runs cold on consecutive shots (about 1 min between shots). Has anyone experienced something similar? Any ideas or suggestions?

Ps. I may try waiting longer between shots to see if it is temp recovery time issue.

Sounds like it could definitely be a temp issue. But the 920 is at least as temp stable or more so than even a GS3 apparently. Did this come on all the sudden? What do you mean by "doing wet" ( I assume just a typo) ? Filming? Do you mean observing the layer of crema on top of the shot?

I can essentially guarantee you it's not your burrs heating up, not in a low use home environment, especially on only the second shot.

If the shot isn't flowing faster on the second shot compared to the first, then it's not likely a goof somewhere in the grinder holding its setting.

Also, if you haven't seen this link, it's super helpful.

Espresso 101: How to Adjust Dose and Grind Setting by Taste

You should have no trouble pulling excellent shots with that gear, over and over.

I have no direct experience; and you may get users answering. But given the size of the brew boiler and its wattage, along with a PID controller that may be overdamped (since overshoot takes a long time to correct -- i.e. no cooling, just heat), it could be that one minute is not long enough for the machine to recover. It's easy enough to check. Grind the two shots at your normal fast pace, but leave, say, 2 1/2 minutes between the shots, and see what happens.

Than you all for replies.
I Fixed typos. Filming was supposed to be Time as in consistent extraction time and doing wet was supposed to be tamping. Gotta love the autocorrect.

Good to know that burr temp on the second shot should be a non issue. Thx

i will try to wait several minutes between shots as Jim suggests.

Now that I'm thinking about what Jim said about passive cooling, my first shot today was running very slow I thought and took about 37 seconds, but ended up tasting so good. I don't know what such a long shot does to the temp of grouphead but I believe that sour typically means that the temp of the grouphead is on the cold side (if temp is the culprit) if everything about prep and extraction process is consistent In any case I will try waiting several minutes and report back tomorrow.

If you have an instant read thermometer you may try measuring the temperature of the first and then shot to see if there is any difference. This may be more difficult to accomplish than it sounds. The receiving cup will have to be at the exact same temperature for each shot. You may be able to get a good reading at the portafilter spout? I would think if it's a temperature problem there would be a significant difference.

Are you using a naked portafilter? Would be interesting to know if the shot is forming properly on the bottom surface of the basket.
Finally, are you plugged into an outlet on a separate breaker? Perhaps the outlet is low on voltage. Can you measure it safety?

If you have an infrared thermometer, they are amazingly inexpensive now, you can read the temperature of the espresso as it emerges from the portafilter if you have a naked one. Sour shots mean too low a temperature or too short a shot or both. The bitter components emerge more toward the end of the shot because espresso making is really a chromatography, because the Rf values for the bitter components, mostly heterocyclic amine compounds, are relatively small making them move down the puck relatively slowly.

I want to thank all that provided advice. As I suspected, it was the grinder. How do I know? Since I had my new grinder, monolith conical for about a month, I've not had a single sour shot, including dial ins. 22sec shot, yummy, 35 second shot,still yummy. Consecutive shots, not a hint of sour.
I have tried two different varios just to make sure I didn't get a bad one, with mixed results at best. I would go as far as saying that vario is not that suitable for espresso. Dial ins were very finicky and coffee consuming. Inconsistent results day to day, or inconsistent consecutive shots, sour shots, etc. Even when all the stars aligned, and espressos came out decent, they were not in the same league as my monolith, or what you would get at a good coffee shop. And you don't have to be a pro either to use monolith. I'm a rookie.
I have wasted so much coffee, until I got my monolith.. I will add that I also had macap m2 grinder with even worse results.
I've seen posts that vario shots were great in some comparison tests. I'm guessing that if enough beans are wasted and a pro is takings time to dial in vario for that particular session, maybe the taste can approach some titan grinders, but I certainly couldn't make it happen.
Hope this helps newbies out there who are struggling like I was (I changed 3 espresso machines and three grinders until I got my monolith).

Cheers

Glad to hear you resolved your issue but to say the Vario is "not suitable for espresso" is quite a stretch. I would say most users, myself included, do not have the issues you describe.

That statement that vario is not suitable for espresso came from an experienced barista initially. I didn't believe him at the time because I was able to get decent results from vario from time to time, thinking that he was just spoiled by high end equipment at the shop. But now I see why he said what he said. Btw, that barista does own vario but uses it for pourover only.
All I wanted to say is mainly this: my lesson is that all my 3 months of mostly frustrating quest into making shop quality espresso/cappuccinos at home boils down to this - that the grinder is the most important item in equation. I would go as far as saying that I believe that you can make a mind blowing cup of espresso with a titan class grinder and $200 espresso machine, while no amount of money spent on espresso machine will get you as good, or rather as consistently great results if you have a mediocre grinder.
When I started in this "slippery slope" hobby, I bought into this theory of matching the grinder to the machine budget wise. I would say that if I only had 1500 to spend on new equipment I would spend $1100 on the grinder and $400 on machine. So something like ceado e37 and revile infuser. But I don't think that makes for a good business model, so I'm guessing that this is the reason shops that sell you equipment don't tell you this. Or maybe they just don't know.

h3yn0w wrote:Glad to hear you resolved your issue but to say the Vario is "not suitable for espresso" is quite a stretch. I would say most users, myself included, do not have the issues you describe.

The issue with the Vario is that it CAN make a fabulous espresso, the problem is that they don't seem to do it reliably. I spent a couple weeks with the Forte which is supposed to the commercial Vario, nothing but frustration, constantly drifting grind size, always chasing shot times in circles. I've noticed none of those issues on the K30.