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Adjusting the Water Dose on the Londinium R
Reiss:
I have been using the Londinium for a few weeks now, and I must say, that as far as cup quality is concerned, it would be difficult to be more impressed with the performance of the machine. Really, well done.
The one issue I have is that the Londinium seems to delver a shot that is twice the volume of a traditional single shot. We've discussed this before, so forgive me if I'm being a pest, but I want to understand the reasons that the Londinium has been preset to deliver the amount of coffee that it does.
To start from the beginning:
When I worked as a barista in my 20s, we used a four group Aurora, a traditional spring-operated lever machine just like the Londinium (it is for this reason that I wanted a lever machine). The machine was calibrated to deliver a single shot, traditionally defined as about 7 grams of coffee per roughly <1.5 ounces of water. A single pull would yield enough coffee to fill a demitasse about 2/3 full. This was our single espresso, and all of the mixed drinks were predicated on the volume of a single shot.<br />
By comparison, the Londinium is calibrated to deliver about 1/3 cup, that is, about 2.7 ounces, or slightly less than 80 milliliters. This fills a traditional demitasse to overflowing. Since you recommend 15.8 grams of coffee per shot, what this means is that, using traditional definitions, a single shot from the Londinium is roughly equal to a doppio. Therefore, to attain the traditional balance between coffee, milk, and foam in a cappuccino, for example, the cappuccino would have to be twice as large if one were to use a single shot from the Londinium. You mentioned that one can just pull the cup before the extraction is complete, but that means 1) the coffee in the cup is a ristretto, essentially, and 2) you waste half the shot. As we discussed previously, one can make two coffees at once with the double-spouted portafilter, but this is not always possible. My wife prefers a lighter roast than I do, for example, so I have to make two separate coffees.
So, my question is: is it possible with the Londinium to adjust the water flow to deliver a single shot as traditionally defined? If I am not mistaken, the hex nut on the group where it connects to the boiler is for that purpose (at least it is on traditional machines).
If it is not possible to adjust the water flow in any way, that's fine, but assuming that it is possible, will the Londinium still deliver a high-quality shot? With a lower dose of water I would obviously have to reduce the dose of coffee used as well, and I assume that this would bring its own problems. I assume, for example, that a reduced dose of coffee would require a finer grind, to compensate for the reduced physical volume of coffee in the basket. I have to assume that there will be other issues that would have to be addressed as well.
I suppose that you do not recommend adjusting the water dosage, but I simply want to know if it is possible. If it is, please explain how to do it and what I would need to do to adjust the coffee dosage and grind to achieve a proper shot.
Thanks,
Earl
I have been using the Londinium for a few weeks now, and I must say, that as far as cup quality is concerned, it would be difficult to be more impressed with the performance of the machine. Really, well done.
The one issue I have is that the Londinium seems to delver a shot that is twice the volume of a traditional single shot. We've discussed this before, so forgive me if I'm being a pest, but I want to understand the reasons that the Londinium has been preset to deliver the amount of coffee that it does.
To start from the beginning:
When I worked as a barista in my 20s, we used a four group Aurora, a traditional spring-operated lever machine just like the Londinium (it is for this reason that I wanted a lever machine). The machine was calibrated to deliver a single shot, traditionally defined as about 7 grams of coffee per roughly <1.5 ounces of water. A single pull would yield enough coffee to fill a demitasse about 2/3 full. This was our single espresso, and all of the mixed drinks were predicated on the volume of a single shot.<br />
By comparison, the Londinium is calibrated to deliver about 1/3 cup, that is, about 2.7 ounces, or slightly less than 80 milliliters. This fills a traditional demitasse to overflowing. Since you recommend 15.8 grams of coffee per shot, what this means is that, using traditional definitions, a single shot from the Londinium is roughly equal to a doppio. Therefore, to attain the traditional balance between coffee, milk, and foam in a cappuccino, for example, the cappuccino would have to be twice as large if one were to use a single shot from the Londinium. You mentioned that one can just pull the cup before the extraction is complete, but that means 1) the coffee in the cup is a ristretto, essentially, and 2) you waste half the shot. As we discussed previously, one can make two coffees at once with the double-spouted portafilter, but this is not always possible. My wife prefers a lighter roast than I do, for example, so I have to make two separate coffees.
So, my question is: is it possible with the Londinium to adjust the water flow to deliver a single shot as traditionally defined? If I am not mistaken, the hex nut on the group where it connects to the boiler is for that purpose (at least it is on traditional machines).
If it is not possible to adjust the water flow in any way, that's fine, but assuming that it is possible, will the Londinium still deliver a high-quality shot? With a lower dose of water I would obviously have to reduce the dose of coffee used as well, and I assume that this would bring its own problems. I assume, for example, that a reduced dose of coffee would require a finer grind, to compensate for the reduced physical volume of coffee in the basket. I have to assume that there will be other issues that would have to be addressed as well.
I suppose that you do not recommend adjusting the water dosage, but I simply want to know if it is possible. If it is, please explain how to do it and what I would need to do to adjust the coffee dosage and grind to achieve a proper shot.
Thanks,
Earl
Comments
a relatively long-winded response is needed to fully answer your question, so thanks for posting here
1. Differences in the solubility of dark roasts (traditional italian) versus light roasts (modern)
I think the starting point for the discussion must be to mention the differences in solubility between a traditional italian espresso roast (fairly dark to very dark) and a contemporary single origin light roast of the kind we are increasingly drawn to. If you are using a traditional italian roast with your londinium then it makes sense to configure your machine in a way that it works well with that roast, but there is no point in adjusting your machine to deliver the traditional italian brew volumes if you are using a medium or light roast
Ways in which we combat the reluctance of a lighter roast offer up its taste;
- increase the dose (of coffee placed in the basket) - the most soluble components of the coffee are carried away by the water at the start of the extraction, with increasingly less soluble components being drawn out of the coffee as the extraction progresses, so one way to combat a coffee that is less soluble is to simply use more coffee
- grind the coffee finer to increase the surface area of the coffee and provide further resistance to the water as it passes through the coffee puck/cake (i.e. so the water is forced through/around the coffee at higher pressure)
- increase the temperature of the water that passes through the coffee (the brew temperature)
- push a greater volume of water through the coffee - based on the idea that even if the solubles drawn from the coffee reduce as each additional gram of water is passed through the coffee, that as long as the solubles carried away by the water are greater than zero that you are still adding flavour to the cup - this idea has its limits though as you can produce a cup of coffee that is excessively diluted in taste if you push it too far, but some people like this taste as they like the filter coffee taste that results, even though it has been produced on an espresso machine.
2. Traditional Italian brew ratios and brew volume delivered (they were all lever machines back then)
My understanding of traditional brew ratios and brew volumes pulled on lever machines is mostly from wandering around italy, in particular Rome & Napoli/Naples. Im not saying my understanding is definitive as i dont want to start one of those interminable discussions where someone replies and says that their aunt is italian and 108 years old and she does it differently; it is simply that, my understanding, collaborated with people like Frank Maxwell (the founder of Fracino) who holidayed in italy about 55 years ago and picked up a small broken down single group domestic lever machine for scrap value and brought it home in his suitcase to have a go at repairing it.
My understanding, like yours is that single doses were 7g and pulled on a single spout portafilter, double doses were 14g and pulled in a double spout portafilter. Bear in mind that the baristas never weighed the doses, it was all done visually (when the coffee was ground at the correct fineness a level cut across the top of the portafilter with the base of a tamper, or indeed a finger, was the dose) and the whole emphasis of coffee roasting was consistency - a blend with so many constituent coffees in it that if one became expensive or unobtainable that it could easily be substituted for another bean and because the percentage was sufficiently low the punters would never taste the difference.
With respect to brew volume my understanding may differ slightly from yours, as i understand that a single shot was always one fluid ounce, or 28g, and that a double shot was made with a twin spout portafilter to make two cups are once and necessitated two pulls of the lever to produce two cups with one fluid ounce of espresso in each cup
3. How a LONDINIUM lever espresso machine differs from a dipper (earlier italian, i.e. pre-dating HX-TS designs) lever machine
The great majority of italian lever machines are dippers as i understand it. That isn't to say that italian lever machines with heat exchangers (HX) and thermosiphons to connect them to the group dont exist, but the majority are dipper designs. This is likely to be because of their simplicity to build and maintain i suspect.
On a dipper design when the piston is raised the water is pushed in from the boiler at boiler pressure. It is important to note that when the brew chamber in a lever machine fills with water that water does not lap against the bottom face of the piston; there is always an airspace between the bottom of the piston and the surface of the brew water below. The volume that this air space takes up is a function of the pressure of the water that is below it
In a dipper the brew water is at boiler pressure, which is going to be between 1.0 and 1.5 bar. As the total volume below the bottom of the piston when it is at its highest point is a fixed volume, then the only way you can get a greater volume of water in is by increasing the pressure, which is what occurs in the current range of LONDINIUM lever espresso machines; at factory settings they deliver water into the brew chamber at 3.0 bar, which greatly reduces the volume of the air between the brew water and the bottom of the piston, and as a result a greater volume of water is able to occupy the brew chamber
4. Adjusting a LONDINIUM machine to deliver a traditional italian brew volume
You will be pleased to know that by simply reducing the secondary pressure switch that governs the pre-infusion pressure that you can make your LONDINIUM R (or indeed the L1, L2, or L3) you can make your machine perform like a dipper (but without the over heating issues that dippers suffer from). Reduce the setting of the secondary pressure switch until the lever is grabbing at about 45 degrees after about 10 seconds of pre-infusion - if you want an even shorter brew volume reduce the pre-infusion time so pre-infusion is unable to fully complete, such that when you release the lever the piston is forcing the brew water above the puck into coffee that is still dry in areas of the puck
This reduction of the pressure at which the brew water enters the group means the air space between the bottom of the piston and the surface of the brew water takes up a greater volume and therefore there is less volume left in the group and so a shot of a smaller volume is produced, in the region of 28g
You should also note that you can fit any nominal 58mm basket into your londinium portafilters, so we sell a 7g single basket for instance, VST make a 15g basket, IMS and others will no doubt offer a 14g basket, and so on; this is the beauty of getting a lever machine with a 58mm group. I simply supply a basket (which by the way is made in the same factory as VST baskets in China, the VST baskets having tighter SPC (statistical process control) parameters, so they will have a higher reject rate which needs to be paid for) that Fracino buy in bulk and use in all their machines. Being tapered it is forgiving which many users welcome when they are getting to grips with their new machine. In time you can treat your machine to all manner of baskets
Please do not open the screw on the top of the group neck - there is nothing under it and in a thermosiphon design it is critically important that the screw makes an air tight seal (it is sealed down with thread sealant). You do not want any form of restriction in the neck of a thermosihon design as it is easy to disrupt the thermosiphon, especially if owners are less than careful with the water that they use in the machine
reiss.
In the Londinium (and others using the same spring-lever group), the displacement (volume pushed by the piston) is significantly larger. At the start of the piston's travel, the spring produces enough force to bear about 9 bars of pressure against a suitable puck. As the spring extends, the pressure tapers off. Most of us who use this type of machine push the cup aside when our desired shot volume is reached, and allow the remainder to flow into the drip tray or an alternative vessel.
You can adjust the various brew parameters to a great extent, and certainly can optimize for traditionally-sized doses and shots, but I believe you will always need to push the cup aside at the appropriate time if you don't want the remainder.
great background information - thanks!
one question regarding the 45 degrees or in general the lever position as an indicator for the 'correct' PI pressure: is the angle seen from the down position of the lever? 45 degrees would be more or less parallel to the PF handle?
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great background information - thanks!
one question regarding the 45 degrees or in general the lever position as an indicator for the 'correct' PI pressure: is the angle seen from the down position of the lever? 45 degrees would be more or less parallel to the PF handle?
hi philip
when the machine is not in use the lever rests beyond vertical by perhaps 10º
when a shot is pulled the lever comes down to a locked out position well beyond horizontal as you point out
so the 45º i refer to means 45º above horizontal, or 45º below vertical if you prefer
kind regards
reiss.