I've been battling sourness since I purchased my machine 3 months ago (first machine ever). I've finally gotten to a point where I'm happier with my shots but my parameters fall outside the recommended range - too long shot time, too much coffee volume etc. At first my shots were sour through and through, I had to dump them. So I kept grinding finer and finer and adding more coffee until hitting 18grams - now my shots are much better than they were, but still not optimal. They start out with a sharp sour taste up front that fades into the chocolate roasty flavors I enjoy. The problem is my brew time (when I start the leaver) is 35-45 seconds and my shot volume is 2.5 ounces (45-50 grams by weight), both of which fall outside the recommended 24-30 second window at 36 grams by weight. If I stop the shot at 2 ounces it's very sour.. if I pull longer to 2.5 ounces it helps balance out the sourness with the chocolaty flavors I enjoy. That's obviously too long a shot and too much coffee. I don't know where to go from here? If I keep grinding finer it takes 15+ seconds to get my first drip... then the shot timer is even longer. Do you think my water temp is too low? Any thoughts on where to go from here?

Profitec Pro 700
Baratza Forte
Counter Culture Big Trouble

Hi John,

I have similar equipment (Pro 700 + Vario) but I myself am battling over-extraction (a bit of bitterness but also overall intensity). In my case, lowering the temperature helped a lot, but I'm not done yet. Can you post your PID parameters? This would probably help diagnose if there is a temperature issue. Otherwise it turns out it's very easy to change temperature on the Pro 700 so play with parameter t1 a bit to see if things change for the better.

Also of course the taste in the cup also depend on the coffee you use, and I don't know much about the Big Trouble and if it prefers higher or lower temperature.

I don't have the PID parameters in front of me but I do remember checking them against the official PDF settings and every setting matched. I did do a rough temp measure with a Thermopop digital thermometer and water from the group falling into a shot glass and my readings were ~195F. Does that seem low or is that about right? I'm guessing it either cools down from 200F as it's falling or my digital thermometer isn't fast enough.

In my case as you perhaps remember, using the recommended PID settings resulted in way too hot water. Your results may vary of course.

I found digital thermometers to be too slow for the job, even using a styrofoam cup: by the time the temperature creeps up on the display, you've let several ounces flow from the group, and fresh water is being let into the brew boiler, lowering the temperature.

In any case I encourage you to set the brew boiler at different temperatures and see if this helps. Try a higher but also a lower temperature, as perhaps what you feel is "sour" is not exactly the same thing as what you get with a lower temperature. Lowering temperature leads to less rapid extraction, which tones down the overall intensity of the drink as well as excess bitterness.

At one point lowering the temperature, it unlocked a rather pleasant, fruity acidity in the coffee I'm using, which I guess would turn into harsh sourness if I lower the temperature much more.

The Pro 700 takes seconds to reach the new temperature so test up to 10F below or above what you're using right now. If you hear flash-boiling in the group head (much the same sound as when using the hot water wand), then you'll know your water is probably too hot for brewing.

Thanks, I'll definitely try adjusting the temp both up and down. Btw, how long is your dwell time? I'm a little confused if I should be counting the dwell time as part of the total brew time.

Also, do you do "pre-infusion" with your Profitec? I'm not totally sure I understand how that works with an E61. Does it automatically pre-infuse or should I be doing this manually?

You need to be plumbed in to do full preinfusion. The e61 does minor preinfusion by itself but its minimal and not that useful I feel.

as for dwell time, I always count it but some say first drop. There isn't much of a consensus and most people end up counting it at 50%.

I know that we should aim for consistency and in that regard, accurate timing of the shots is important. That being said, the shot timer on the Pro 700 is too useful to not use --- it's just that I don't take the recommended shot times at face value. I found out that most of the time 25 sec is on the short side so I mostly aim for 30 sec.

As for pre-infusion, there was a great thread a few months ago about pre-infusion on the E61 group. The short version is that there are two different things that people call "pre-infusion" on the E61.

First, you can get the lever up mid-way, which may open up the brew valve before the pump starts on some machines. (On mine, the cam position and the pump switch are placed in such a way that the pump starts a bit *before* the valve opens, so this kind of pre-infusion doesn't work on my unit). Now with the brew valve open, nothing much happens unless your machine is plumbed in. If it is, under line pressure, water is pushed into the group. If it isn't, there's only a few drops that will eventually make their way under vapor pressure. This is also called "pre-wetting".

Second, there's the "built-in pre-infusion" which refers to the fact that inside the group, there's a valve that is pushed closed by a spring. When water enters the group and pressure rises, the spring is pushed back gradually. The effect of this is to lower the pressure on the coffee at first --- pressure slowly rises as the spring gets harder to push back. When the valve is pushed back all the way, water is allowed to enter a small chamber behind it. When water is allowed to get there, pressure behind and before the valve is equalized and the valve snaps shut. The full pressure is then applied on the coffee puck.

The whole process is designed to apply a smooth pressure profile on the coffee -- it takes a few seconds after switching the pump on for the full pressure to be applied. This can be heard as well as seen, as typically coffee will start flowing only once full pressure is applied.

SonVolt wrote:Do you think my water temp is too low?

Yes.

Rich

What are you using for water?

I live in an area with low hardness so I'm just using filtered water from my fridge's filtration system.