# Old Londinium & quick preheating



## Deidre (Aug 13, 2019)

What is the best approach & method to speed up the preheating process of the older Londinium model? I currently wait an hour or so for it to warm up on its own, but on occasion, would like to do things more quickly.

I realize you can do flushes to speed things up, but need guidance on the overall procedure & timing. How many flushes, are they full flushes or mini-flushes, how many minutes for this to bring machine up to optimal brewing temp (and what is that ideal benchmark temperature?). I want to get things hot enough, yet not so hot, I ruin the shot.


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## MediumRoastSteam (Jul 7, 2015)

Another trick you can do - I did on an e61 machine - is to wrap a towel around the group.


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## Fez (Dec 31, 2018)

On the odd occasion I've had to do this on the LR, I usually turn it on, wait for the first 10-15 mins. Then about 3-4 small flushes over the next 10 mins.

I don't bother too much about the exact timings. And you know it's fully warmed up the group is too hot to touch


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## MildredM (Feb 13, 2017)

We bought ours a little gift with this in mind last year funnily enough . . .


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## coffeechap (Apr 5, 2012)

Firstly it won't get to hot from flushing the group. To get it up to temp in 15-20 mins, allow the boiler pressure to come up to its setting, then to a cup full flush of the group, allow around 2 mins then do another, so will feel the temp rising in the group, repeat a few times and you will be up to temp. It will natural come up to temp in around 45 mins if just left to it's own devises.


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## Mrboots2u (May 10, 2013)

leave it on all the time.....


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## mathof (Mar 24, 2012)

Deidre said:


> What is the best approach & method to speed up the preheating process of the older Londinium model? I currently wait an hour or so for it to warm up on its own, but on occasion, would like to do things more quickly.
> 
> I realize you can do flushes to speed things up, but need guidance on the overall procedure & timing. How many flushes, are they full flushes or mini-flushes, how many minutes for this to bring machine up to optimal brewing temp (and what is that ideal benchmark temperature?). I want to get things hot enough, yet not so hot, I ruin the shot.


 I use a technique Reiss recommended some time ago on the Londinium site. When the boiler is up to the pressure that makes the pressurestat cycle (about 10 minutes), I let it reach the top of the cycle and then pull the lever to the point where water begins to dribble from the group. As soon as the pump kicks in, I let the lever rise again; and then repeat the process until the group is sufficiently hot (I have a thermocouple permanently mounted on the side of the group). Additionally, because I don't want to waste the Volvic water I use to fill the tank, I collect the water from the group in a pyrex measuring cup and pour it back in the tank after it has cooled down.


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## Deidre (Aug 13, 2019)

mathof said:


> I use a technique Reiss recommended some time ago on the Londinium site. When the boiler is up to the pressure that makes the pressurestat cycle (about 10 minutes), I let it reach the top of the cycle and then pull the lever to the point where water begins to dribble from the group. As soon as the pump kicks in, I let the lever rise again; and then repeat the process until the group is sufficiently hot (I have a thermocouple permanently mounted on the side of the group). Additionally, because I don't want to waste the Volvic water I use to fill the tank, I collect the water from the group in a pyrex measuring cup and pour it back in the tank after it has cooled down.


 Thanks for those details! Truly helpful! And, @MildredM, I shall also knit up some wooly mittens, hat & scarf, to make it feel warm & cozy!☺☕

@mathof I have a couple more queries with your comments in mind:

What is the actual temperature reading registered on your thermocouple, when you feel it high enough for your first shot?

If the pump is running, is there any reason I can't flush a bit at the same time it is running? Or, should I not be pulling on the lever at all if/when the pump is running (green light comes on)? (Same question applies for the hot water tap & steam arm: is it a bad idea to operate these if green light is on/pump is running?)

I have thought about recycling water back into tank☺.... glad to hear I am not the only one! (Do you think reboiling water affects end flavour at all? ( I ponder this, amongst other minor matters at times!??)


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## Fez (Dec 31, 2018)

My fear with recycling the water is that what if some coffee particles make it into the water from in around the shower screen. Surely that's a risk to the pump? For the cost of the water, surely that's not worth it. Or if you're trying to be eco friendly then stick that water into your kettle instead


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## PPapa (Oct 24, 2015)

Yeah I wouldn't recycle the water back. Could use it for watering plants, dish water, etc?

Admittedly, owning a machine with 2l+ boiler that requires a long warmup isn't the most eco-friendly solution. I had days where I had my LR turned on for most of the day, but had a couple of cups only. I am now more disciplined, turn off the machine earlier (would have a pourover if I fancy another coffee) and try to offset the environment by walking where possible, reducing waste and eating less meat.


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## Deidre (Aug 13, 2019)

Just tried the "dribble effect" & it works really, really fast... no time at all, and the group is super hot to the touch! I would say 15 minutes start to finish (turning on machine, waiting for pressure to kick in (10 minutes), then follow with dribble strategy (5 minutes). Plus, I get some upper arm strength/resistance exercises ;>) . Wowzers!


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## Stevebee (Jul 21, 2015)

Deidre said:


> What is the actual temperature reading registered on your thermocouple, when you feel it high enough for your first shot?


 I have the original L1 plumbed in with a thermocouple also permanently attached to the group. Also have a bar towel formed into a sleeve for the group if ambient is low (Used as one of the machines at Farmers Markets.)

The thermocouple is positioned in the place Reiss recommended in one of his posts on the side of the group, cable tied with some cork keeping in tight to the group and also not affected by air movement. With pressure set to 1.2bar at home the temp settles at 85 to 86 c and stays at this all day without the towel. With the towel on it raises it to 87-88c at home but only up to 85 outside. So when my machine hits 85 I know it's reached it stable state. I don't pull shots before this.

To get it up to 85 quicker I use @Coffeechap method of larger flushes - I find that smaller flushes don't seem to work as well for me.

The 85 is the external temp of the group obviously not the temp the coffee is brewed at


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## Deidre (Aug 13, 2019)

@Stevebee

Thanks for those details! Great information, and I appreciate the help!

Has anyone been able to determine the correlation between the actual water brewing temperature & the thermocouple reading at the group head? Do we know approximately the brewing water temperature reflected by that grouphead temperature?


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## Stevebee (Jul 21, 2015)

Deidre said:


> Has anyone been able to determine the correlation between the actual water brewing temperature & the thermocouple reading at the group head? Do we know approximately the brewing water temperature reflected by that grouphead temperature?


 I did some analysis when I first got the L1. Look in the lever forum titled "Londinium 1 temperature profiles" posted on 11 Jan.

Regards flushing, did attempt a fast warm up this morning.

Red Light on L1 turns off. 34c

Flush 1 up to 50c, wait for red light off

Flush 2. Up to 60c, wait for red light off

Flush 3 up to 70c,

Flush 4 up to 75c

Flush 5 up to 80c

Flush 6 up to 84/5c my target

Each flush was about 200ml. Time from turn on to 85 was just under 15 mins.

Without flushing this normally takes over 45 but nearer an hour but I have it on a timer so in no rush.

Machine is plumbed in , normally I just wait but this was to show in an emergency!


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## mathof (Mar 24, 2012)

Deidre said:


> Thanks for those details! Truly helpful! And, @MildredM, I shall also knit up some wooly mittens, hat & scarf, to make it feel warm & cozy!☺☕
> 
> @mathof I have a couple more queries with your comments in mind:
> 
> ...


 85.5C, thermocouple placed on group near neck joint

You can use the lever while the pump is refilling the boiler. Same for steam and hot water

I do a visual check to make sure there are no coffee particles in water I return to the tank. Water is continually being reboiled from cool unless you run the machine 24 hours a day, 7 days a week


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## PPapa (Oct 24, 2015)

Stevebee said:


> I did some analysis when I first got the L1. Look in the lever forum titled "Londinium 1 temperature profiles" posted on 11 Jan.
> Regards flushing, did attempt a fast warm up this morning.
> Red Light on L1 turns off. 34c
> Flush 1 up to 50c, wait for red light off
> ...


How does this compare to brew water temperature?

I admittedly had few cups with 15-20 min warm up time, pour milk in it and just chug it. My machine is on a smart plug, so the only times I do this are 4-5AM and I am barely awake anyway.


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## Deidre (Aug 13, 2019)

> Look in the lever forum titled "Londinium 1 temperature profiles" posted on 11 Jan.


 I will keep searching the londinium site, but have not been able to find this post on the londinium site... I did enter "Londinium 1 temperature profiles" in the support page "search" box, and got a list of 6 unrelated topics/posts. (To be honest, the londinium site can be very frustrating... quoted links no longer exist, and when I want to revisit a discussion I read before, it cannot be found again! The site has good information, but it has been challenging to navigate.)


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## Stevebee (Jul 21, 2015)

It's on this forum in the same sub section as this post @Deidre


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## Stevebee (Jul 21, 2015)

PPapa said:


> How does this compare to brew water temperature?


 To be honest I didn't pull any until the group was up to temp so don't know


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## MildredM (Feb 13, 2017)

https://www.coffeeforums.co.uk/topic/44453-londinium-1-temperature-profiles/?tab=comments&do=embed&comment=641722&embedComment=641722&embedDo=findComment#comment-641722


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## Deidre (Aug 13, 2019)

Stevebee said:


> It's on this forum in the same sub section as this post @Deidre


 Oh, sorry! I misunderstood & went searching the Londinium forum!?‍♀


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## Deidre (Aug 13, 2019)

@Stevebee Found the link, with help from you & @MildredM! Excellent information there! Wow!?


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## Stevebee (Jul 21, 2015)

Good practice, especially with the older L1, is to do a mini flush after the shot once the portafilter has been removed.

Not only does it clean the screen but it also importantly stops any chance of a thermosiphon stall happening.

Without a flush it sometimes does happen and your group temp will fall. A quick flush gets the thermosiphon back into equilibrium but you will have to wait for group temp to recover. That's why I always flush straight after the shot.


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## Deidre (Aug 13, 2019)

@Stevebee

What does "thermosiphon stall" mean? What causes it? (I have seen it mentioned a couple of times, but don't really understand what this is all about. I realize it results in a temperature drop, but don't know or have any idea about the whys & wherefores.)


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## Stevebee (Jul 21, 2015)

In a thermosiphon there are 2 pipes coming from the boiler/heat exchange pipe. The top one supplies hot water to the group, heats the group, this cools the water and as colder water is denser it moves down to the lower of the 2 pipes which returns the cooled water to the boiler. So water is continuously circulated through the group in this way to keep the group at a constant perfect temp for brewing. This will continue all day if no shots are pulled.

if hot water stops circulating into the group this cycle stops and with no hot to cold circulation going on the group temp gradually falls, and will continue to fall until you restart the thermosiphon circulation, typically done by a short pul of 50-70ml. This introduces hot water which then cools, returns and so on. The stall happens on the L1 when the temp diff between the 2 pipes reduces stopping the movement of water, air getting past the piston seals etc.. The newer seals the L1 uses help with this issue.

A simple flush alieviates this and cleans the screen


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## Junglebert (Jan 7, 2019)

Reboiling water will only ever have a negative effect on the taste, it dramatically changes the mineral content.



> I have thought about recycling water back into tank☺.... glad to hear I am not the only one! (Do you think reboiling water affects end flavour at all? ( I ponder this, amongst other minor matters at times!??)


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## 4515 (Jan 30, 2013)

Junglebert said:


> Reboiling water will only ever have a negative effect on the taste, it dramatically changes the mineral content.


 I get that boiling water changes the temporary hardness for water but this happens when the water is boiled once. Can you explain what impact reboiling water has on mineral content and the impact on taste.

My machine is left on all day but I'm trying to understand how I'd get around avoiding the reboiling of water as theres always water left in the boiler after Ive made a drink..


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## Deidre (Aug 13, 2019)

Years ago, I read that "studies had shown"? absolutely no taste difference when making tea with water that had been re-boiled. This finding seemed sacrilegious & highly suspect! But, I confess, I do cheat & use some old water & some fresh occasionally when making a cup of tea for just myself. I fear I might be cast out if I risked doing that with my visitors' cups of tea!??

With my espresso machine, the boiler is sending brewing water back & forth within its pipes numerous times. I do wonder about the impact on an espresso shot's flavour, as a result of this water recycling.?


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## iroko (Nov 9, 2012)

I warm the cup from the water tap so some fresh water goes into the boiler every day.


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## 4515 (Jan 30, 2013)

@Junglebert could you explain the impact of boiling water on minerals


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## mathof (Mar 24, 2012)

working dog said:


> I get that boiling water changes the temporary hardness for water but this happens when the water is boiled once. Can you explain what impact reboiling water has on mineral content and the impact on taste.
> 
> My machine is left on all day but I'm trying to understand how I'd get around avoiding the reboiling of water as theres always water left in the boiler after Ive made a drink..


 Today, I drew a half glass of boiling water from the water spout on my Londinium 1 and let it cool to room temperature. Then I filled an identical glass to the same level from a bottle of the Volvic water I use in the machine. The tastes are markedly different. The water straight from the room temperature bottle is soft and pleasant to drink; the cooled down water from the boiler has a definite taste of minerals. It reminds me of tap water in some cities. It's not particularly unpleasant, but it's not desirable either.


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## Deidre (Aug 13, 2019)

Hmmm... what are we to do then, I wonder, to ensure the best tasting espresso....assuming we want to avoid watering the plants with reboiled Volvic water, that is?! (I add fresh water to the machine each day, but I don't drain the tank.)


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## mathof (Mar 24, 2012)

That mineral-rich water may be better for making espresso than freshly boiled water. I don't know, but it's possible that it helps in some way to extract more of the coffee solids from the beans.


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## 4515 (Jan 30, 2013)

mathof said:


> Today, I drew a half glass of boiling water from the water spout on my Londinium 1 and let it cool to room temperature. Then I filled an identical glass to the same level from a bottle of the Volvic water I use in the machine. The tastes are markedly different. The water straight from the room temperature bottle is soft and pleasant to drink; the cooled down water from the boiler has a definite taste of minerals. It reminds me of tap water in some cities. It's not particularly unpleasant, but it's not desirable either.


 Interesting that theres a difference but that difference will be there in all water that is heated up in the machine. Not sure if this can be avoided and therefore in every coffee. By boiling you remove some of the temporary hardness and calcium and magnesium carbonates will precipitate out of the water. I'm wondering if this is the taste that you describe as they are the main 'ingredients' in volvic.


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