? Making double shot without using double wall?

GuyDeMont

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Jan 31, 2015
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Hello,

I have a Breville 900XL Dual boiler espresso machine and a Krug grinding machine. I am successful at making single shot espresso and hitting the 8 bar pressure mark using the single shot single walled portafilter cup.
My challenge is when trying to make a double shot espresso using the single walled double shot portafilter cup. No matter how I try (changing the grind, tamping pressure, tamping depth) I can never reach more than 4-5 bar.

I have to revert using the double walled double shot portafilter cup to get to the ideal extraction pressure (8 bars). I find using the double walled double shot portafilter cup makes the espresso too bitter and off tasting.

Would you have explanations why I am not hitting the right pressure using the single walled double shot portafilter cup and how I should proceed to successfully use the single walled double shot portafilter?

Thanks!
 

Coffeefix

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Dec 17, 2014
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I'm a technician for commercial machines and it sounds like your machine runs in a different way to that which I'm used to seeing - 8 bar would be considered slightly low as most commercial machines run at 9bar. You probably have a smaller vibration pump that takes time to build pressure too?
I have to admit, I'm a little confused... You have a single filter holder (1 x spout, small filter) and a double filter holder (2 x spouts, deeper filter) yes?
You get a decent single espresso from the single F/H but the double doesn't build up enough pressure and tastes off?
Well, presuming that your single espresso is of good quality, rich flavour and thick crema then this seems strange as it's usually the single filter that needs a little extra effort to get the best results?
Putting the single filter into the double filter holder will produce two very weak coffees (unless you like them very very short!) no matter how you try...
If you double filter isn't doing a good Job:

1. Are you putting enough coffee in?
2. Correct grind?
3. Everything ok? No leaks, coffee grinds getting into the cup?

It would appear that the gauge you are reading is attached to the group itself and shows the pressure therein. Given that the single is ok it seems most likely that the amount of coffee and the grind are most likely wrong? Your coffee is probably a bit coarse or not enough - the single filter has less holes and is shallower, it could be that by tamping a bit more it is overcoming the problem of the coarse coffee? Difficult to say.

How long does it take to make an espresso, say 24ml in seconds? How does it look?
Coarse coffee or not enough makes for a fast, weak, bitter espresso, not enough of the rich acidity is extracted from the initial part of the process. Crema is thin and pale.
 
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GuyDeMont

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Thanks for thanking the time to provide feedback CoffeeFix!

One clarification; I made an error in reporting the number of bars my machine produces. It hits 9 bar of pressure every time I use the single shot, single walled portafilter cup.

You are correct that there's a more holes on my double shot single walled portafilter cup than my single shot single walled cup (about 2.5 times the amount). However, on my single shot and double shot portafilter cup which are Dual Walled (as Breville names them) the number of holes are the same for both portafilter cups. The perforated area is just a bit less than the surface of a dime.

I am already at the smallest grind level of my grinding machine. I have put various type of pressure in trying to be able to use the single walled double shot portafilter cup. Nothing worked; the highest I get, by putting lots of pressure to the grinds is 5-7 bar.

From your feedback, if I understood you correctly, it sound to me the problem lies with my grind machine which cannot produce a more finer grind to be used when I use the double shot single walled portafilter.

Let me know if you have other ideas I should look into (e.g. changing the double shot settings on my machine for example longer infusion time ?)


I'm a technician for commercial machines and it sounds like your machine runs in a different way to that which I'm used to seeing - 8 bar would be considered slightly low as most commercial machines run at 9bar. You probably have a smaller vibration pump that takes time to build pressure too?
I have to admit, I'm a little confused... You have a single filter holder (1 x spout, small filter) and a double filter holder (2 x spouts, deeper filter) yes?
You get a decent single espresso from the single F/H but the double doesn't build up enough pressure and tastes off?
Well, presuming that your single espresso is of good quality, rich flavour and thick crema then this seems strange as it's usually the single filter that needs a little extra effort to get the best results?
Putting the single filter into the double filter holder will produce two very weak coffees (unless you like them very very short!) no matter how you try...
If you double filter isn't doing a good Job:

1. Are you putting enough coffee in?
2. Correct grind?
3. Everything ok? No leaks, coffee grinds getting into the cup?

It would appear that the gauge you are reading is attached to the group itself and shows the pressure therein. Given that the single is ok it seems most likely that the amount of coffee and the grind are most likely wrong? Your coffee is probably a bit coarse or not enough - the single filter has less holes and is shallower, it could be that by tamping a bit more it is overcoming the problem of the coarse coffee? Difficult to say.

How long does it take to make an espresso, say 24ml in seconds? How does it look?
Coarse coffee or not enough makes for a fast, weak, bitter espresso, not enough of the rich acidity is extracted from the initial part of the process. Crema is thin and pale.
 

Coffeefix

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Dec 17, 2014
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United Kingdom
Difficult to comment when I'm not familiar with the machine, all I can do is relate to commercial stuff.
Personally, I'd concentrate on the single walled filters for now - can't think of a reason why twin walls would be an advantage? At least not on a commercial machine. Normally there are less holes in a single because the "puck" of coffee is shallower and the water would wash through faster and in doing so extract less flavour.
If you are not getting enough "pressure" in the double filter holder yet the single is ok it sounds like it could be related to the amount of coffee you are putting into the filter?
What sort of grinder do you have that doesn't go fine enough? Espresso grind is often not as fine as people think!
Try putting a couple of shots of ground coffee from your grinder into the palm of your hand, then squeeze it by making a fist - when you open your hand out flat your hand will be messy but you should have a lump of coffee sitting on your palm that "cracks" in one or maybe two places? If you get it like this it might not be perfect but you shouldn't be far off "espresso" grind. Next, pack plenty of coffee into the filter and make a few coffees. A fine tune of the grinder, coarser to speed things up, finer to slow it down and you should be able to produce something near an espresso.
This of course all depends on several other things, fresh coffee, clean machine, correct water temperature, flow and pressure (gauges can lie), tamp pressure, water quality... Oh I think barometric pressure and how far off your birthday is also have an effect.
 

itsabean

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Nov 23, 2014
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South FL
Guy--Seems to me that Coffeefix has offered some helpful ideas. One factor that he mentioned strikes me as being crucial, and that is the freshness of the beans you are grinding. I've been learning with a new Breville BES870XL semi-auto. Even though I had read here and in the manual about bean freshness, it is a lesson my machine has confirmed. With beans beyond their fresh period, I cannot get enough extraction pressure no matter what I do. Reducing grind size and increasing dose doesn't help. I have yet to understand exactly why beans must be fresh for a good extraction, but my machine certainly is aware of how fresh the beans I feed it are, and it responds accordingly. The machine, like yours, was supplied with both double-walled and single walled portafilter filters. I have not used the double wall filters, and instead went right to the single walled ones. I've been using the double shot single walled filter most all the time. My understanding is that the dual-walled filters won't give you a true picture of pressure developed during extraction, but the single-walled filters do. It's as if the machine is telling me loud and clear--feed me fresh beans if you want proper pressure; if they're stale, you will only get under-extractions.
 

shadow745

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Aug 15, 2005
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Central North Carolina
Coffee freshness is often the most overlooked variable in the equation. Even coffee sitting in a hopper overnight won't extract anything like it would when just poured into the hopper. I would say toss the lame double wall baskets aside and tweak your variables with the standard baskets. Keep in mind that a single basket is tapered whereas most double shot baskets are straight wall. This will affect pressure somewhat as well due to the flow restriction. If Breville is as serious as they claim regarding equipment and specialty coffee they wouldn't include dual wall baskets to begin with.

Yes it may be time for a more capable grinder as well.

Reading pressure will help you get in the ballpark, but ultimately taste, texture and color will help you fine tune it over time. Even in a commercial setting I never set up the pump pressure based on a number, but rather what was in the cup. The whole 9 bar/200 degree/7-14 gram blah blah blah B.S. is just that. There are no rules in espresso really, just what you like as an individual.

If your puck is a bit soupy the coffee is more than likely old and/or under dosed. If the puck is rather dry and not fully saturated then you're probably over dosed. Each machine/group/basket type will vary a few grams either way.
 
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itsabean

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Since the Breville 900XL dual boiler HX sports some higher level features, I am surprised that dual walled filters are among the supplied accessories. They're included with the 870XL with the manual's description that they are helpful for newbies to espresso making who may not feel ready to move up to single wall filters.
 

shadow745

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Aug 15, 2005
1,592
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Central North Carolina
I once thought dual wall baskets/pressurized portafilters were OK training aids for beginners, but really they are nothing but crutches. Most of what is learned through the use of those items is tossed out the window when using a standard non-pressurized setup and it's almost like starting over.
 
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GuyDeMont

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Jan 31, 2015
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Thanks for all your feedback! My knowledge of espresso making has gone up!

Just a few comments. Indeed my single wall basket is tapered for the single shot not the double shot. I also agree the double wall basket, al least for the double shot, produces an off tasting espresso to my liking.

What I am still puzzled about though is coffee freshness. What I don't get is this; for the same coffee using the same type of grinding why would the single shot single basket produce a perfect espresso but when I try it with the double shot single wall basket it does not produce the right pressure? I am not sure the freshness of the coffee is at issue here. Your comments above makes me think the coffee grinding is probably the source of my problem when I do double shot espressos.

Someone else suggested that I try to use a slightly coarser grind (rather then going finer) when using the double shot single wall basket and put a bit more pressure when packing the portafilter. I'll give it a try this weekend.

If ever I look to buy a new coffee grinder, what would be a good coffee grinder to purchase? What I am using now is a Krups ($100.00) but unfortunately I am now at the finest it can grind. This is why I am curious to know what other ones should I look into. Interestingly ( and surprisingly) I had a Breville coffee grinder for a few days ($150.00) but had to return it to the store. It simply did not grind fine enough for the Breville 900XL dual boiler. I was not even getting the right pressure for the single wall single shot espresso basket.

Thanks again.

Guy
 
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Coffeefix

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Singles and double filters often make different espresso! The skill is in getting the best from both.
It seems many people don't realise that filters come in different sizes too! Plenty of miss matched filters are used in cafes every day.
7g of coffee in a single rarely makes an equivalent espresso to 14g in the double for instance, treat them as different filters not simply one single and one double the size of the single.

Don't know much about the specifications of domestic grinders but If you look at the best commercial grinders they are notable for he following:
1. Well made. The grinding plates are held in an accurately made, well designed solid part of the grinder that brings the plates together in a very parallel fashion when adjusted and run. If the plates don't come together properly you effectively get a less accurate grind - a mix of fine and coarser coffee.
2. A slow spinning, powerful motor. Less speed = less friction. Ground coffee is cool as it exits the grinder. Grinder still grinds quickly as the powerful motor allows larger grinding plates. Compared with a 1400RPM grinder the difference in crema/flavour is amazing.
3. Larger diameter plates are a sign of a more powerful motor and faster grind generally, some like "conical burns" although to be honest I think these are slightly overrated? Low speed and more power are better IMO.
4. Less important in domestic grinders - cooling mechanism. Busy commercial grinders are likely to get warm through constant use and the better ones have effective cooling fans/control these days. Another reason why fully automatic espresso machines get a hard time - the internal grinder is small (space is an issue) and parked right on top of a boiler! Heat dries out the oils people!

How many people have splashed out on a trendy espresso machine for their kitchen and then bought a cheap grinder to sit next to it? You wouldn't put cheap tyres on a Porche 911? Would you?
 

itsabean

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Guy--It gets curiouser and curiouser. I'm wondering why you couldn't get your former Breville grinder to produce fine enough. My built-in conical burr grinder in my Breville can produce a too-fine grind. The sweet spot on its adjustment appears to be up near the top end on the coarse side! Otherwise, it will get too fine.
I noted Coffeefix' comment about single and double shot filters producing different expresso. My speculation is that perhaps this is due (at least in part) to the sloped shape of the single shot filter basket allowing a higher pressure to be reached during extraction than the straight-walled double shot filter allows. If so, in light of my experience to date, it leads me back to bean freshness. Nobody to my knowledge has disagreed with the idea that under extraction (pressure too low) is directly linked to bean freshness. My understanding is that freshness falls way off and is gone in somewhere around 3-4 weeks after roasting.
 
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GuyDeMont

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Thanks for the advice CoffeeFix!
All interesting comments. Before I got the Breville 900 I was looking to but a machine with an integrated grinder.
Reading point No.4 makes me think it's a good thing I opted for separated machines.
 
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