Posted Fri Dec 24, 2004, 7:24am Subject: Bitter Shots?
Hi Everyone,
I am new to this, and am working with an Andreja Premium and a Macap M4. I am working with fresh beans that I roasted yesterday in my IRoast. I've been trying to dial in my grind/tamp and got it today where the pour starts around 9-10 seconds and I am getting a brownish crema throughout the pull and stopping at at around 25 seconds or so for roughly 2 ounces. I'm using 18 grams of coffee in a double basket. My shots while I was dialing them in were really bitter. They got less bitter and I went finer with the grind. I finally ended up with a grind where the shot wasn't even starting until ~15 seconds and that ended up tasting *really* bitter so I figured I overdid it and went back a notch. The problem is, even the best one still tasted bitter.
First, could the bitterness have to do with not letting the coffee not rest long enough? If that is not it, I am thinking it's a temperature thing? I am doing the flush, waiting until the flow settles down through the PF, then pulling it, wiping it out. Grinding my beans and dosing into it, levelling and then tamping. Locking the PF back into the machine and pulling my shot.
Posted Fri Dec 24, 2004, 8:23am Subject: Re: Bitter Shots?
Well it sounds like you've just about covered the bases. The only things I can humbly suggest are:
Try running your flush a little longer, and actually pull the PF as soon as water starts to flow. Wipe it and start dosing coffee into the basket before you stop the flush (this should lower your brew temp, try for a 6-8 ounce flush)
I have also noticed that for finer grinds and ristretto shots the pucks may have some moisture on top right when I first pull the PF, especially if I remove the PF immediately. My pucks are still reasonably firm though, not soupy.
You may want to experiment with resting longer, maybe 2-3 days. I almost never use coffee the next day after roasting. Some blends are best after 3-4 days.
You may even want to try adjusting the p-stat to get the boiler temp reduced a little. What is your boiler pressure now? Do you have a way to measure brew temp?
Posted Fri Dec 24, 2004, 12:14pm Subject: Re: Bitter Shots?
Thanks for the help Jon.....I'm going to give your idea of pulling the PF as soon as the water stars to flow a try. I have the feeling it's a temperature issue. And I would say the puck is reasonably firm. I'm not sure on the boiler pressure, I'll have to pay attention to the guage next time I try a shot.
Tim - you can look at the BOILER pressure anytime the machine is warm. It should be around one bar, maybe as high as 1.2 bar. I run mine from 0.9 to 1.1 bar.
The BREWING pressure (pump pressure) during the shot may be anywhere from 7 to 11 bar depending on your conditions and setup. Most believe that 8-9 bar is ideal.
Posted Fri Dec 24, 2004, 12:40pm Subject: Re: Bitter Shots?
Hi Tim ... Sounds like we have had similar experiences.
I had the same concern about bitter with my new Andreja last week, so I checked the temperature using the styrofoam cup approach and found after a 6 oz flush it was 208F and occasionally higher on shorter flushes. I checked the boiler pressure (the upper guage) and saw it was bouncing arround between 1.3 and 1.4 so checked in with Chris Coffee who said they leave the shop set at 1.2, but they drift a little in the first few weeks. They gave me instructions for backing it down a tad. IIRC, Bob Yellin ran some experiments and concluded that 1.05 worked well for him, so I moved mine to 1.1 to start.
The process is
UNPLUG THE MACHINE
Lift off the cup warmer tray as if you were adding water. Remove the black plastic cap (I had to pry it with a small screwdriver under the edge). look straight down with a flash light and you will see one large screw and a tiny one. With a very long (9-10" skinny screwdriver, turn the BIG screw about 10 degrees CLOCKWISE (to lower pressure and thus temp).
PLUG IT BACK IN, run some steam out and pull some water through the head, then see where the guage settles. Adjust further as neccesary. repeat flushes, etc.
I took 3 tries to get it settled so that it bounces between 1.1 and 1.05 ...It looks like I might have tightened the dead band accidentally (I think that is what the little tiny screw controls).
The shot taste improved dramatically.
My pump pressure (the other guage) maxes out at about 10.8 and I get fluid appearing closer to 5 seconds after start when the group has had a long time to warm up and been flushed. I then get 22 sec 1.5 oz shots with 15 grams at the grind I use. Your experience (7-15 secs to fluid) seems long.
I hope this is useful food for thought. BTW ... unplug the machine when you work on it ... they emphasized that I could short out the system with that screwdriver.
Kitt's advice is very good, especially about working with the boiler pressure. There's no problem working with a small deadband (some wish it were that tight).
As far as how long it takes for flow to start, there are several variables that could affect that. I notice that it takes longer with more coffee (my triples commonly take up to 15 seconds to start flowing). If it's a pump flow issue then that would be worth investigating (but as long as your cooling flush has nice flow I wouldn't worry).
Here's the very beginning of a triple ristretto from yesterday, taken right at 14 seconds into the pull. (I've been trying to get a better picture, hopefully someday...)
Posted Fri Dec 24, 2004, 2:07pm Subject: Re: Bitter Shots?
Thanks Jon and Kitt, I think you've nailed it. My Andreja has been on all day and the boiler pressure is smack dab at 1.2 right now. Seems to me I have watched it bouncing around between 1.2 and 1.3. I'm going to back it off down to 1.1 to start and see what kind of results that gives me. Regarding the flow, my cooling flush flows just fine so I don't believe it's a pump issue. I was getting flow starting somewhere around 5-7 seconds, but went to a finer grind and more coffee in the quest for a less bitter shot and that is what affected the beginning of the flow time which jives with Jon's thinking.
You certainly should give the lower setting a try. However, getting the right brew temperature from an HX is more a question of adapting your technique to accomodate the machine, not adjusting the machine to accomodate your technique. More specifically, lowering the pressurestat on the Andreja Premium (a) decreases the flush amount and (b) increases the rebound time. My guess is that the bitterness you describe came from too long a delay between the flush and start of the shot ("rebound time"), which for a high pressurestat setting like 1.4 bar would only be around 15-20 seconds.
I used to diddle with the pressurestat settings, but now I usually compensate by changing these two variables. There are some secondary benefits of a lower pressurestat setting such as reduced flush amount / frequency, less energy consumption, less wear on the pressurestat contacts, reduced heat loss to the room, etc., so the pressurestat setting is by no means arbitrary. But it definitely isn't a temperature regulator in the same sense as the thermostat of a non-HX machine.
Posted Sat Dec 25, 2004, 6:39am Subject: Re: Bitter Shots?
Dan, thanks for your thoughts on the matter. I understand what you are saying regarding juggling the variables and adapting technique. I also appreciate the links as it helped me understand the issues more clearly. If I am understanding correctly, lowering the pressurestat will increase my rebound time, which I think is what will really make a difference. Since I am new to this and my technique is understandably somewhat rough :), the increase in rebound time will give me more time to get my act together and get everything right. Without going through the process of getting a thermocouple and hooking it up for precise temp. measurements in the PF, will using a thermometer and a styrofoam cup get me close enough so that I have a better chance of being in the correct temp range when I pull my shot?
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