I have heard several times how you can burn coffee in a Moka pot but am not sure I understand how. Is it really that much different from a vacuum brewer in ease of burning coffee? I would think you would need to leave the Moka pot on the burner long enough to boil all the water out of the bottom. It would then probably melt the gasket between the top and the bottom and get the top part of the pot hot enough to burn the puck and the coffee up north. I suppose I could try it with my > "Cherie" but I'm just not quite that <Snip> Terry F joshm writes: <Snip>
On Sunday, October 27, 2002, at 04:22 AM, TFisher511 wrote: <Snip> Burn is not quite the right word. Coffee extracted with water above 200 F extracts undesirables from the grounds and gives it what is called the "burnt" taste. Anything that uses steam pressure to push water through a puck of coffee, moka pots and steam toys, will expose the grounds to temperatures well above the 200 degrees F and the coffee simply does not taste good. I have found that a moka pot works well at about 7,500 ft elevation and I attribute that to the lower temperature at which water boils way up there, 198 F. The main purpose of pump driven espresso machines is to use a thermostat to determine when the temperature is right to allow a pump to force the 195 to 198 or so degree F water through the coffee. Temperature surfing is the process of using what manual control we have over the espresso machines to try to get water at a perfect temperature to the puck and overcome some of the limitations of the automatic controls in our machines. Vac pots use steam to push the water up to the brewing pot but the water that gets to the coffee is well below boiling which allows the vac pot to make a "unburnt" coffee. Jim Gundlach roasting over pecan wood fires in La Place, Alabama homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast
Jim, The extraction at too high water temperature is the only thing that made sense about burning coffee in a Moka pot short of a meltdown. I had not considered that part of the process and that is a very good point. That would seem to insinuate that Moka pot coffee brewed at under 7500 feet would probably have that too high water temp characteristic. I don't know. The Moka is an interesting little device but it is not my favorite extraction method considering the fooling around, the cleanup and the flavor. Terry F jimgundlach writes: <Snip>
Myron, See comments below: On Sunday, October 27, 2002, at 08:04 AM, Myron Joshua wrote: <Snip> If you open the top and watch the pot operate you should see a smooth dark liquid without bubbles at first. This is when you have water without steam pushed through the puck. As the process goes on, you will see bubbles added, this means that the water is too hot and quality will degrade. If you don't stop the process you will finally see steam shooting through with small droplets of coffee spraying around. <Snip> That is why yours has the pressure valve. It is a safety device, not something that improves the quality of the coffee. <Snip> Just the opposite, the higher the pressure the higher the temperature the more bitter the cup. <Snip> The 4 cup model probably gets hotter and stays hot longer than the 2 cup model. You probably will not be able to make as good a coffee with the 4 cup model. This is the reason you do not see ten shot group heads on espresso machines. Jim Gundlach homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast
Thanks for the explanation Jim. But isn't it true that a Moka pot also has steam collect in the bottom chamber that Pushes WATER and NOT STEAM through the grinds? Once this water leaves the pressurized chamber the water might turn to steam (while it is going through the grinds??) and this may be a dangerous situation. Perhaps the extra weighted piece that sits on the orifice of the Moka pot stem on the Brikka System prevents this from happening and that is why it gives a better (and not bitter) cup. Best, Myron "Trying his darnest to get as good cup out of the 4 cup brikka as he does out of the 2 cup model!"
On Sunday, October 27, 2002, at 07:34 AM, TFisher511 wrote: <Snip> I am not sure where the threshold would be, I've only tried it at 325 and 7500 feet. The one brewed at 7500 feet was quite good, the ones brewed at 325 feet were only drinkable until I tried my first one from a pump machine. Someone else said they got good results at about 3000 feet. Jim Gundlach homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast
Jim wrote: <Snip> This is why I always stop the procedure before all the water goes through the stem. I usually pour off before the bubbly stuff comes through. I have tasted what continues to flow after i pour off and it is definitely very inferior. The Brikka System includes a weight on top of the stem that casues the pressure to be a bit higher and effects water flow. It seems it holds the water back and then lets it come out more rapidly. Perhaps this way more water flows through the grinds before the boiling water has a chance to reach them. I swear that this system does produce something very Crema like-oils that stick solidly to the cup. This could be covering the burnt taste. You are right that this added weight would also cause the water to be a higher temperature. But the outcome is a smoother cup. <Snip> Yep, i thought of this as well. Some have suggested preheating the water so that the Moka pot has less chance to heat up. I also thought of using a higher flame to speed up the process.
Jim wrote: <Snip> However, if you poke around on the coffeetec website I posted earlier, you will find a 6-group machine! -- Rick homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast
I saw that machine! Do you know how much foot traffic it would take to keep it running at full cap? You'd need an aircraft hangar for the lines. The boiler was a beaut, though. Quite a conversation piece, but overkill in my estimation. Jim G.
On Sunday, October 27, 2002, at 04:22 PM, Rick Farris wrote: <Snip> Exactly, six heads that will produce a double shot each. When you want to produce more you have to go to more groups rather than bigger groups. There are groups that take filters that hold the coffee for ten or twelve shot pulls. Jim Gundlach homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast
Judging from the responses, I think I am one of the few people who has actually measured the temp of the coffee as it comes out of the spout of a Moka pot. It is well below boiling. The principle of the moka pot is not that much different than that of the vac pot, it's just in reverse: where the vac pot pulls the water through the grounds via pressure, the Moka pot pushes the water through. Many people have expressed concern because the water bubbles in the top of the Vac pot, calling it "boiling". That has been shown to be a misconception. The water expands and rises way before it boils.The same thing happens in the Moka pot. I would suggest, however, that you not use too high a flame under the pot when you use it, and to cut the flame just as the coffee is beginning to slow. Practice will show you the sweet spot... The use of a thermometer should put all your concerns to rest. Remember, the Moka pot is rumored to be the preferred method of brewing, not only in Italy, but in most of Europe and South America, so it shouldn't be too much of a risk to try it.:-)... Ciao, Angelo <Snip> homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast
On Monday, October 28, 2002, at 02:01 PM, Angelo wrote: <Snip> I don't think there is sufficient pre-boiling thermal expansion in the volume of water that we put in these small pots to brew any coffee. I just put a measurement vial in the microwave with 45 ml of 58F water. I put it into the microwave and brought it up to 205F and at most it increased in volume by 0.5 ml. And, most of that was probably due to the evaporated bubbles along the side of the vial. In a moka pot, the first water may lose some of its heat before it makes it to the top but there is not enough pre-boiling thermal expansion to even get the coffee wet in a moka pot. Jim Gundlach homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast