I've noticed a problem recently when I make more than one shot. The first comes out exactly as it should. Timely pour, excellent color, crema, taste, weight, etc. However, the second shot (and any shot afterwards) is consistently terrible. Gushing flow, very little crema, extremely sour, etc. I am utterly perplexed as to what could be causing this and I didn't find much upon searching (most people seem to have bad 1st shots and good from then on). Does anyone have any tips for making my latter shots as good as the first one?

Some information on my routine after at least a 10 minute warm-up:
1) Blank shot to warm basket, group, and cup
2) Dose (by time) into PF, WDT, nutate, tamp
3) Lock and pull the shot
4) Excellence
5) Knock used coffee out of PF
6) Wipe basket with dry towel to remove moisture and grounds
Then I repeat 1-3 exactly and consistently get a terrible shot. I would blame my technique, but day after day it's the same: excellent first shot and a bad second shot.

First thing that strikes me is you need to tighten the grind (go finer) after your first shot - Your word "gusher" gives me that notion. I have different equipment than you - but generally adjust grind a bit tighter after the first shot. (My first shots are not always worse compared to latter ones) However, there may be some thing else going on because of the extreme difference in shots for you... (Maybe something going on with excessive pressure buildup in your machine as the machine heats more?)

See what others say that may have similar equipment...

How long between the first shot and subsequent shots? Have you weighed your dose after loading your pf to make sure it's actually the same each time?

A 10 minute warmup is not much even with that little guy. You may want to give it more like 15-20 before you use it. I would guess either your subsequent shots are way off on dose which can easily be checked with a scale or your temperature is way off. An extremely cool shot will gush through the coffee as well.

Dose. Well, I set my vario to grind 14g in 7.4 seconds and it seems pretty consistent on that whenever I weigh it.

Temperature. Okay. So I usually let it warm up around ten minutes (the manual only recommends 6 ), but I don't see a huge difference in the first shot as long as it's at least 6. I guess the longer I let it warm up the more stable the subsequent shots will be. I don't time it, but I probably give it around 3 minutes between shots (time to clean and prepare the basket again). I'll try a longer warm up tomorrow; to be safe I'll do 20 minutes.

So even a well-distributed/tamped puck will gush with a cooler temperature?

One more thing I do before each shot is a small (~2 oz) flush to clean/heat up the group and basket. Not giving the machine enough warming time explains it losing heat and gushing the second shot. Is this even a good thing to do before shots, given my machine?

maccompatible wrote:The first comes out exactly as it should. Timely pour, excellent color, crema, taste, weight, etc.

What a fortunate man you are Matthew. You get one good shot! If only I was as blessed ....

Ken

kchris wrote:What a fortunate man you are Matthew. You get one good shot!

Well, keep in mind, a good shot for a newbie like me will be a sink shot in a couple of years. Ha.

I always single dose, and at some point I realized that my old technique when I was pulling 2(or more) shots wasn't working. I'd weigh out enough beans for each shot, dump them in the grinder and grind them all at once. My first shot came out good (or as I had dialed it in at least) and the rest would be too fast.

Now, I weigh and grind each shot before putting the next shot's worth of beans in the grinder, and my subsequent shots are much more consistent. Now, I know that you're grinding differently, but it's worth keeping in mind that very small differences in how you grind can have very big effects on the shot. It took me a little while to figure out where the difference between my first and later shots was coming from.

Here's what I'd try. Grind your first shot, and set it aside, grind a second shot (maybe even wait a minute) and then pull your first shot of the day with the "second" shot's beans. That should help you pinpoint whether the difference you're seeing is coming from the machine or from the grinder. (and then you can pull your second shot with the first shot's beans too, and see what happens

Going down Tristan's line of thinking, without bean weight above, your grind will be coarser. So if you are only putting two shots worth of beans in the hopper, it makes sense that your first shot would be fine and the second one gush. If you're keeping a full hopper, then I'm clueless.

I used to have a Carezza, and I would let it warm up for half an hour before I used it. So I think maybe that might be where the sourness comes in, maybe it's warm enough for one shot but cools down too much for the second one. I used to have trouble with the second shot being a gusher too, because I also measured out beans for two shots and ground them at once, and had more in the first shot than the second. It helped when I started grinding the two shots separately. Gaggias seem to do well with a bit of updosing too, maybe try sixteen grams in a fourteen gram basket.