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caffeinegeek

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About caffeinegeek

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  1. I was surprised nobody mentioned Pannarello? I discovered this is the design of the Delonghi frother I tried with a stainless 6-10mm DIY thread adapter I made from stainless using taps, dies and tube. An expert in fluid mechanics could explain why this design is so good at producing micro foam easily from small milk volumes every time? In fact, you can create microfoam like a soufle which stays in the cup for 10 minutes +. The trick with Pannarello tips is drawing air down the outer sleeve. Not only does this introduce air without any special angles, technique or milk rolling, but the air cools the steam as it enters the milk. This means you do not get a high volume high temperature steam jet entering the milk, bouncing off the bottom of a small pitcher and heating the milk too fast before it gets enough foam. The Pannarello tip takes longer to froth - about 40 seconds. The Delonghi tip I tried has a sliding air shut off and the trick is to cut off air at about 50 deg.C when there is sufficient foam and continue steam heating to the final temperature. This answers my question to my problem - Plenty of perfect milk frothing every time using a Pannerello frothing tip, even with different milk. The best for me so far is Asda own brand full cream.
  2. Hi all, can somebody tell me what is the outside diameter size (mm) of the steam tube on a Gaggia Classic? Thanks
  3. Thanks, I can try that. I agree it may be possible to find a technique and work fast, so I'm prepared to take longer then move up to more holes if I want faster steaming? I'll try blocking up a hole, but this will change the steam distribution as both holes are offset from the tip centre. With the single hole tip resting at the popular angle on the jugs pour lip, then moved to the side I'm getting a good swirl action in the milk without the ultra rapid fast temperature rise. I've been working on the principle that if I can produce plenty of good quality micro foam, I won't have a problem producing less, whilst tip depth can still give me heated milk without foam? I don't want to hog a thread about milk when coffee aficianados concentrate on shots. But it's frustrating when you think milk should be the easy part.
  4. So now I believe this problem arises using a commercial machine which is more suited to high volume coffee turnover in a busy shop? The volume of milk being frothed or steamed with microfoam will be a lot more than the single cup volumes I'm starting with. My Fracino Contempo 1E has a large 7 litre copper boiler, therefore plenty of steam volume maintained at the optimum 1 bar pressure. With their standard 4 hole steam tip and milk volumes around 125-150ml, the superheated steam volume and capacity to heat a small amount of liquid is huge.150ml of milk at 7 deg.C can reach 70 deg.C in less than 10 seconds. Frothing requires the physical action of 'rolling' the milk. My standard steam wand has no air admittance port I could find to mix air with steam and getting the right air mix is down to tip technique. But such a high steam volume will cause rapid heating of the small milk volume first, allowing insufficient time to roll the milk and consolidate air into it before it reaches the optimum 60-65 deg.C. In the hands of an experienced Barista it may be possible to get these small milk volumes frothed o.k. But since I've started looking carefully at the quality of frothing and many online videos, I see there's a large variation in results obtained for cappucino and latte, which are not obvious just looking at the top surface of the finished cup. I can make froth but microfoam, steamed milk that pours like Guinness looking active in a glass with micro bubbles rising upwards and stable has eluded me? Advice so far has been to concentrate on milk, temperature and technique. It's true that getting good results from a small milk volume is hard but why? - It's because the steam heating is too fast to control the amount of air through the milk stage at around 50 deg.C, although I agree it's possible with the right technique if you can work VERY fast. I decided on 2 approaches to test my theory: My steam wand with a 4 hole tip pushes out steam fast and furious, so I can't see any issue with the boiler but I can easily change the steam tip. The second test would be to try a sophistocated steam tip designed to allow air to mix close to the tip. Ideally I wanted a commercial quality steam tip. I found a steam tip spare sold for the Delonghi ECAM 22.320.SB. This is mostly plastic with a 6mm angled steam tube, a single 1.2mm hole and clever nozzle and air admittance, but won't plug in directly to a 10mm OD wand. This was my first alternative test nozzle temporarily fitted to my steam tube with silicone pipe and clips. This nozzle is a concentric design. The steam jet itself is specially moulded and there's an outer tubular 'shield' through which air is admitted. I think the idea is you don't need to incline the tip, just sit it below the milk surface and the shroud draws in air above reducing the problem of large air bubbles forming and breaking at the surface. This is similar to how a gas blow lamp or bunsen burner works. In just 2 tests with no special technique I could produce gloopy long lasting Guinness like foam in 150ml of cold milk taking about 40-50 seconds. My second approach was to try a Rancilio Silvia V3 single hole tip and compare results with the Delonghi frother. What I disliked about the Delonghi frother is its multiple components that are not so easy to clean as a standard tip and it's more domestic quality parts than solid all metal commercial. The Silvia V3 single hole tip produced the lower steam volume and much slower temperature rise I was looking for and therefore easy to find the transition temperature where the milk would roll and keep rolling a lot longer. As with other standard steam tips, it relies on technique to angle and position the steam tip in the jug, but it's far more controllable. For a commercial coffee shop, the steaming time of up to 50 seconds per 150ml is probably too long, but the foamed milk quality is excellent. The Delonghi frother still had the edge as it was pretty idiot proof and very little skill is needed, apart from looking at the digital milk thermometer. I have decided to cut the standard 10mm steam pipe about 150mm up from the steam tip and fit a threaded stainless adapter. This will allow me to fit the Delonghi frother, revert back to the standard tube and different tips, or experiment with my own version frother using an outer shroud like the Delonghi. I hope this helps those using commercial machines at home struggling with milk frothing to get good results. As I get more practice with the single hole tip, I may move back to 2 or 4 holes, but at the moment I like the control I'm getting with single hole and time to froth is less important to me than the result.
  5. With the stock 4 hole tip it takes about 12-15 seconds for the milk to go from 7-70 deg.C steaming at 1 bar. I think I might be getting somewhere because I'm sure now my technique is fighting the huge amout of steam coming out and the fast temperature rise. Somewhere around 60 deg.C I start to get the large bubbles and after that large bubbles just keep coming. This morning a Breville steam tip arrived. It's the one with the plastic push up and down sleeve to select hot milk or cappucino. It's short stubby 'L' shaped steam tube is 6mm OD whereas my Fracino is 10mm OD and 8mm ID. With some temporary silicone tubing, I attached it to my steam wand, plunged it into supermarket semi skimmed milk. It took longer and the temperature rise was slower but I got nice micro foamed milk from a small starting volume of about 125ml. Now I know this frothing tip is a designed venturi and sliding the selector just covers the air hole. I dismantled it and the single tip hole was about 1.2mm. I'm not trying these things to compete with baristas, but then single cup coffees with small volumes of milk with no waste is my challenge. If I was frothing 250ml + milk each time I think it would be easier. I bought some Cravendale whole milk and tried it with the stock 4 hole tip. The cold milk swirled with more turbidity, but that might be expected anyway compared to semi skimmed. The small volume frothing result was similar but the foam seemed more stable and sat longer without collapsing, but then this milk is twice the price! So I'm back wondering about trying a single hole standard type steam tip first to give slower heating? I shall also be engineering the Breville steam tip with a more permanent connection to my standard steam wand and do it in a way that allows me to go back to the standard tip. Mods always need a revert back exit plan! I'll let you know with some photos how it's working out if I don't give up fighting the Captcha.
  6. Regular supermarket fresh semi skimmed - Waitrose, Sainsbury - they all give me the same results. But I'll give the Cravendale full fat a try if they are using better cows.
  7. Thanks for the 'tips' (pun!), I've watched several videos but they don't tell you what to do when you don't get the same result at the end? My milk volume is 100ml which added to a single shot fills my latte glasses. That small milk volume might explain why I'm generating bubbles and coarse foam at the surface? I don't see why there should be objections to using a wine cooler? Mine is compressor driven with tight control of temperature, adjustable down to 4 deg.C, has a smaller space without the door always being opened for access to food and now we drink more coffee than wine.
  8. Thanks, I've made a small step in progress: I do use a thermometer and aim for 65 deg. C & no more than 70C. I changed the steam wand tip from 4 hole to 2 hole. Most fridges of the Eco kind like ours set their fridges to 10 deg.C when the Eco button is pressed which is a trap for the unwary! I could drop the fridge temperature but the wine cooler will do 5 deg. C which is a smaller space and doesn't get the same frequent use as the kitchen fridge. The problem as I see it now is my milk volume is too small for single cups causing the milk to heat up and aerate too quickly due to the small volume. The larger air bubbles are getting through faster before I get nice micro foam. The larger bubbles tear the milk fat apart and once this stage is reached there's no more micro foam . A larger pitcher gives better results because the frothing to final temperature can be slower and I'm doing good cappucinos, but the micro bubble froth for latte is still eluding me? Once the milk starts to froth I'm getting larger froth bubbles sitting like foam on top of the milk. Just for an experiment I've ordered a Breville auto frothing tip to try on my 10mm steam wand to see if getting air into the milk through a venturi tip design gives a better froth. I'm also aware that steam tips come in different hole sizes as well as the number of holes. I think my problems arise because I'm not in a cafe business frothing 1/2 litre of milk at a time. Just to give me an idea, how long should it take for a given volume of milk in your pitcher to reach temperature? I didn't think frothing fresh milk for micro foam would be so hard. The boiler is putting out steam at 1 Bar with no water after purging the wand and the only thing left can be the tip, how air is mixed and my technique?
  9. Thanks, that ties up when I said frothing 2 cup volumes seems better. But if you want just one cup of coffee, do you froth more milk and throw milk away? I suspect the best milk froth occurs when the milk is coldest and my small milk volume heats up too quickly? I think I will try some milk in my wine cooler which is at about 7 deg C and a lower temperature than the fridge. When I do the hand hold temperature check I find my coffee seems too cool? Perhaps that is how it should be compared to boiling water over instant. I was in Italy last year during Winter and the first Latte I had seemed too cold for my taste, but I was told the Barista had been taught by his parents over many years so I wasn't going to argue! Does your milk froth pour out of the jug nicely or stick around the sides like mine?
  10. I can only comment on my 'all manual' method where I have control over all the elements. I use a Mazzer Jolly grinder I modified to provide adjustable timed bursts. 4 bursts gives me a single shot load which I frequently check for weight, but I can tell from the finished tamped height if it changes. I aim for and get a single shot time of 20 seconds with 8 bar pump pressure. The shot times change according to which shop beans I use, how dark they are and how old they are, so I want to start roasting my own. The Mazzer micro grind adjuster only needs a very small change to optimize the grind and pour time. I watch the crema as the shot comes out and occasionally I will extend the shot if I think there's some more left. IMHO the grinder and the grind are the biggest factors in achieving consistent shot times. If I'm lazy and the shot drips out slower taking up to 40 seconds, I might leave the grind settings as they are.
  11. Hi, I have an old 'traditional' machine with a 4 jet steam wand and normal steam pressure at 1 Bar. Whatever type of cold milk I use, frothing starts producing what I think you all call the micro foam. I personally find the milk to cool for my present taste and keep frothing longer until I hear the tone change from the steam wand. At this point the milk gets hit by lots of large bubbles and can rise to twice the starting volume, but the froth then seems too coarse with too much air and collapses quickly. I am generally frothing a small volume sufficient for a single shot cup or latte and I can get some better results starting with a larger volume of milk. Whatever I do, I can never get any improvement and produce a more solid froth for latte art, although what I produce seems to be like the coffees I get abroad in the run of the mill bars ( not Costa!). Where am I going wrong? Is it a limitation of my machine? Do good milk frothers always use air injection or special steam tips or higher steam pressure? Another problem I have is the froth sticking to the inside of my stainless frothing jugs. I've checked inside and they are not highly polished which I think would allow the froth to slide out better? Are there better frothing jugs? I've noticed some commercial places spooning out their froth rather than pouring it.
  12. My old Fracino failed last week. Symptoms were : 1. Normal pump pressure for start of brew. 2. Nothing from brew head. 3. A few seconds after selecting expresso type, all leds flashing and audible alarm. There was no 'click' heard from the group solenoid so I suspected the error alarm was caused by lack of water flow being measured to the brew head. Tested the solenoid coil Parker YB09 P/N 304398 and found it open circuit. Ordered new coil. D.c resistance measured @ 900 ohms. Warning: Do not power these coils unless they are fitted on the valve stem, otherwise excessive current will flow! I wonder if others have had to replace the group head solenoid coil? My old coil was stamped Tu=50 deg.C, whereas the new coil had no temperature markings. I looked in the Parker catalogue and all coils for this valve VE128 V have a 50 deg.C ambient temperature rating. On my Fracino machine the group head temperature is maintained by syphon flow and the solenoid is directly coupled to the brass body components. I would expect the ambient temperature around the solenoid to be above 50 deg.C? My valve has a stainless U channel cover over the valve so I might consider replacing it with polished perforated stainless sheet. I checked the Parker catalogue for alternative higher temperature coils, but there were non.
  13. I've been using my Mazzer Jolly a while now with the funnel mod. Static on grinds isn't too bad, but there's always some grind left behind to fall out several minutes after filling the filter. Static is produced on the grind because the beans have been roasted and are so dry they are a high voltage electrical insulator. After mechanical grinding, the grind particles take on an electrostatic charge helped by oils from the beans acting as another good insulator. Electrically, your ground coffee is similar to high insulation plastic: Once the grinds have taken on the charge they will be attracted to any earthed part of the grinder. I don't get the grind shower and spatter some get, just a small amount left stuck to the inside of my funnel which drops down later. The closest analogy is charged laser toner sticking to the collector drum. The amount of static you get and its nuisance will depend on the dryness and depth of roast. A very dark roast will lightly carbonize the beans and they should take on less static. A mild roast with some oils remaining will be a good static charge retainer. After some searches I found what is frequently referred to as a 'hack' requiring water to be dropped on some kitchen tissue and then 3 or 3 drops squeezed out into the been hopper. This introduces humidity or water vapour on to the beans which is relatively conductive to static charge and stops the grind particles taking on a static charge and sticking together. It was after reading this that I thought the logical cure for bean static had been missed. And so I removed my small size hopper from the grinder and waved the steam wand over the top a couple of times. With the lid replaced on the hopper, there was humidity trapped inside and no static after the grind, even a few days later. Since anybody sincere about getting good coffee should have a decent grinder and steam wand, it seemed the logical way to avoid static and get consistent grind weights for each shot.
  14. There are more knowledgeable people here than me but I have been all over my old Fracino. I regard it as having a cloned E61 head with their added solenoid removing pressure to drain. I didn't spot it straight away but what surprised me the second time I was dissasembling their group head was the tiny circular stainless steel filter screen in a chamber on the top after the brew water inlet. This is followed by a jet with a VERY small orifice of about 0.7mm dia. This was a surprise when you look at the size of everything else. But explains how the small amount of brew water passing through the portafilter basket is kept at near constant pressure during the shot pull. The gauge is on the brew water flow output before the jet. I only see a small change in pressure when a shot is pulled and I can now see why. It also explains where the generally quoted figures of expected water volume come from when a shot is pulled with an open portafilter. The brew water volume delivered is determined by the pressure set on the pump, the size of the jet and the time water flows. If we time the flow over 25 seconds for say 9 Bar pressure, the amount of brew water delivered to an open filter should be similar machine to machine. This also assumes the pump pressure control is good and maintaining its pressure when loaded. A good point was made about mains water inlet pipe kinking, This aspect of the design on my Fracino was really bad and took some time to get a kink free routing. A rotary pump using a mechanical pressure off loading valve needs the pump to be fully charged on the water inlet side to allow it to regulate the set pressure under all load conditions. A kinked pipe could starve the pump and reduce outlet pressure when needed for the shot. I agree that if pressure is not reaching the filter basket it can only be lost in a few circumstances - The pump pressure is 'sagging' which should be evident on the gauge, water is being bypassed via the OPV, water is going to drain (visible) or if the group head has this small jet like mine it could be partially blocked? On my Fracino I had to buy an unusual long reach metric socket to remove it for cleaning. I've been looking at these pressure gauge modded blind portafilters and I'm not happy with them for my Fracino? When my shot starts, the flow meter is expecting some (small) flow as brew water is sent through the charged puck. If no flow is sensed, my machine goes berserk into alarm mode and the same thing happens if I try a rubber blanking disk. I've concluded the only way to get a useful pressure reading is to measure pressure in a fully charged portafilter as it is passing brew water. Unless you drill holes into the group before the filter basket you can't do this. One way I'll try is to fit a needle valve after a pressure gauge fitted on a blind portafilter. For my test I shall swap out a 3/8" spout. The out flow from the needle valve can then be adjusted to be the 25 second discharged shot volume. The presssure reading will then be more representative of real life because it will correctly show if the pump pressure is sagging (in my case) after the flow jet, whilst my machine is working under its normal conditions with a measured flow and no alarms. By adjusting the needle jet I should be able to simulate finer coffee grind to see how well the pump pressure into the filter basket holds up. These blind portafilters are everywhere on Fleabay with just a pressure gauge attached. Somebody please tell me why these are so popular for fault finding when they don't allow normal water flow? If other group heads have a small jet orifice like mine, there will be an unstable pressure reading as the brew water through this jet is pushing against a relatively large volume of trapped springy air.
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