After reading up on the issue of water debit and flow rate I decided it was time to mod my Linea Mini and install a low flow gicleur (or is it gigleur? and why can't we just call it a restrictor instead of using weird unpronounceable words?).

The process really wasn't too bad so I thought I'd do a quick write up to assist others who may want to do this. Or at least you'll have a better idea about what you're getting into.

First step is to get hold of a new gicleur. The standard size in the Mini is 0.8 mm. Most of the high end LM machines use a 0.6 mm. The part number is L087/GI/6. It's $3.26 from LM. Unfortunately shipping will cost you over 3 times that, but they ship it in a big box. You may also want to purchase a new o-ring for the boiler (part number H.1.023), but it's $50! Seems like an outrageous amount for an EPDM o-ring, so I did the job without one figuring I'll replace it if it doesn't seal.



Next step is to download the Linea Mini parts catalog which has some exploded parts diagrams so you can see what you'll be doing. Here is a link: Linea Mini Parts Note that you'll mainly be referring to pages 22, 26, and 28.

Next step is to open up the machine to get access to the boiler. First remove the grate and panel for the cup warmer by removing 5 screws. Then remove the cover above the group by removing 4 screws. Make sure to carefully set the parts aside. Once you've done that you should be looking at this.



This will give you access to the boiler. But before you mess with the boiler you will need to do a few other things first to allow access to it. Remove the handle from the brew paddle - there are two screws underneath. Then you will need to remove the paddle group frame (part #4 on page 6 of the parts catalog). You do this by removing the 4 nuts and washers on the inside. Be careful not to drop any. Remove the paddle frame. This will allow you to move the paddle assembly and switch out of the way so you can access the boiler without having to disassemble the paddle assembly.

Now you can remove the boiler cover. There are 5 large hex bolts to remove (one of each of the corners and one holding the paddle assembly to the frame, note that the 2 front bolts also hold the paddle assembly). You will need a very long 6 mm hex wrench or a vise grip wrench with a shorter hex wrench might work. I found that these bolts were torqued very tight. Loosen the top center bolt first then the other four. Once you get all the bolts out you can now move the paddle assembly forward through the opening in the front of the group cover where the paddle frame was. I found it helped to use some tape to hold it in a forward out of the way position - see picture below.



Gently remove the cover from the boiler, which will be full of water. I used a straw to suck the water out of it so I could access the gicleur. The gicleur is threaded into a fitting at the back of the boiler. It would be super easy to remove if the frame weren't in the way as it sticks out plenty. But with the frame over the top (see picture below) it's awkward to access. I tried needlenose pliers but couldn't get a good grip on it. However, with some small vise grip pliers I was able to clamp them onto it and make the first quarter turn counterclockwise. After that I was able to unscrew it the rest of the way with my hand. I threaded in the new gicleur and made sure it was tight.



At this point if I had a new gasket I would have replaced the old one, but instead I just coated the top of the old one with a little Dow 111. Put the boiler cover on and threaded in the hex bolts tightening them a little one at a time like lug nuts on a car wheel until everything is good and tight. At this point I turned on the machine to do a pressure test. I turned the pump on and off a few times, checked around the boiler cover for leaks, and it all looked good. Success!

Next step was to shut the machine back off, then I reinstalled the paddle frame (tricky unless you have small hands and fingers), paddle handle, group cover, and finally cup warming cover and grate.

The entire procedure took about an hour. I tested my flow rate after and it was about 75-80 ml per 10 seconds, compared to 120+ ml per 10 seconds before. It was DEFINITELY worth it. The improvement in my shots was noticeable. Shots pull very slowly and look like those thick syrupy Slayer shots. In the cup the difference was also noticeable with more sweetness and nuanced flavors. For under $20 I'd say this is the single best change you can make in terms of bang in the cup.



If you try changing out the gicleur on your Linea Mini and run into any issues call LM tech support and ask to speak to Chris. He walked me through the above beforehand and was super helpful.

Good luck fellow Linea Mini owners, hope this helps.

I did this today as well

I didn't remove the plastic cover where the paddles arm swings, that would have given me more room to work.

I didn't find any difficulty in the switch. I just used a very small pair of channel locks(tongue and groove pliers) to unscrew and screw in the gicleurs. I think it only took me about a half hour.


Keno was your Gicleur brass? Both the installed one and the replacement appear to be out of stainless steel.

Totally worth it IMO, I get a lot more time before blonding now. I've pulled about 6 shots with the .6 and it's already apparent this was a great decision.

Not2Bitter wrote: Keno was your Gicleur brass? Both the installed one and the replacement appear to be out of stainless steel.

Totally worth it IMO, I get a lot more time before blonding now. I've pulled about 6 shots with the .6 and it's already apparent this was a great decision.

My old gicleur looked like it was brass. The new one was definitely stainless. Amazing what a difference 0.2 mm makes!

One word of caution. For anyone considering this change, make absolutely sure you are using water with low hardness. When I spoke with Chris at LM he said the main problem they have dealt with on the Linea Mini is clogging of the gicleur (i.e., the stock 0.8 mm gicleur) even when using water that is within the high range of LMs water quality recommendation. I closely inspected my boiler and old gicleur and there were no signs of scale buildup. If you aren't carefully monitoring your water this might not be a good idea. Check your flow first.

My machine is brand new so maybe they changed them since then.

Due to how easy this is to do, the way LM recomends, and the way it's very obviously designed to be removed I would definitely discourage anyone from trying to remove it from the back like another member suggested.

Funny you mentioned how much difference .2mm makes, I took both of them and tried to blow through them like a straw and I could tell there was a big difference. I was really surprised.

I live in an area with soft water and I have a softener to make sure. My old house had hardness issues and I had to check the water often to make sure my softener was doing he trick.

Keno, nice write up as always. Nice to see you and Not2Bitter has gicleurs that were able to be unscrewed easily. I was just glad to have a LM tech in the house.

Glad you guys are enjoying the mod. The low flow difference is stunning.

Now you have that out the way there are just a few things left to get CAD (cntl alt delete) shots.

-Low pressure 6 bar, during a shot
-95 degree F beans, most don't have a Mythos One Clima Pro but you can microwave or sous vide beans to 105 then grind to simulate
-Lower dose, 17-18g in 17g LM VST
AND
-Grind Finer, you will also need to grind finer overall for the low pressure, heated beans and lighter than normal tamp.
-Level, dead level, tamp
-Lighter tamp, 22 pounds
-Longer time 4-10 seconds, longer for lighter roasts
-Lower temp, the darker the roast the lower the temp, I'm down 6 degrees F from 203 to 197 using a dark medium roast, Vivace Dolce.

Kipp wrote:Now you have that out the way there are just a few things left to get CAD (cntl alt delete) shots.

-Low pressure 6 bar, during a shot
-95 degree F beans, most don't have a Mythos One Clima Pro but you can microwave or sous vide beans to 105 then grind to simulate
-Lower dose, 17-18g in 17g LM VST
-Level, dead level, tamp
-Lighter tamp, 22 pounds
-Longer time 4-10 seconds, longer for lighter roasts
-Lower temp, the darker the roast the lower the temp, I'm down 6 degrees F from 203 to 197 using a dark medium roast, Vivace Dolce.

Thanks Kipp! Good suggestions. I've already dialed down the pump pressure to 6 bar. Have been using 19g in the LM 17g basket so will try reducing the dose and grinding finer. Probably also need to reduce my temperature a bit with the longer extraction. Working on one variable at a time so as not to get totally confused.

Thanks, you're welcome. I'd say jump in all at once with those starting points and fine tune for your beans from there. There were over 30,000 shots pulled to dial in those parameters.

keno wrote:will try reducing the dose and grinding finer.

I edited above post as I forgot to mention grinding finer, much finer if you do all the steps

Kipp wrote:Keno, nice write up as always. Nice to see you and Not2Bitter has gicleurs that were able to be unscrewed easily. I was just glad to have a LM tech in the house.

Glad you guys are enjoying the mod. The low flow difference is stunning.

Now you have that out the way there are just a few things left to get CAD (cntl alt delete) shots.

-Low pressure 6 bar, during a shot
-95 degree F beans, most don't have a Mythos One Clima Pro but you can microwave or sous vide beans to 105 then grind to simulate
-Lower dose, 17-18g in 17g LM VST
AND
-Grind Finer, you will also need to grind finer overall for the low pressure, heated beans and lighter than normal tamp.
-Level, dead level, tamp
-Lighter tamp, 22 pounds
-Longer time 4-10 seconds, longer for lighter roasts
-Lower temp, the darker the roast the lower the temp, I'm down 6 degrees F from 203 to 197 using a dark medium roast, Vivace Dolce.

I agree with basically all of this kipp. I'm at 18 grams in a pseado basket. The lower flow seems to have caused the blonding to take so long I can pull much longer shots. I'm surprised how much better the lower pressure tamp works, I've never found that tamp pressure made a difference before. The tamp difference is most likely due to a lack of PI ramp up. I'd like to get Rick Bonds speedster style expansion valve to smooth that out.

Not2Bitter wrote:I agree with basically all of this kipp. I'm at 18 grams in a pseado basket. The lower flow seems to have caused the blonding to take so long I can pull much longer shots. I'm surprised how much better the lower pressure tamp works, I've never found that tamp pressure made a difference before. The tamp difference is most likely due to a lack of PI ramp up. I'd like to get Rick Bonds speedster style expansion valve to smooth that out.

Try the Eazytamp 5 Star Pro. 22lbs of perfectly level tamp every time.

I found grinding directly into portafilter and two finger-tip tapping on side of basket to level and get all the grinds touching all of the side evenly then tamp light creates the most consistent, non striping flow of any technique.