dual wall or single wall filters for my coffee machine and how many grams of coffee?
"We are having debate in the office about dual wall or single wall filters (we have the Breville dual boiler manual machine). What is better with your coffee beans? Also – for the large filter basket how many grams should we be using for one coffee, and how fine?"
That's a pretty advanced debate, it's a pretty small percentage of coffee lovers that care to think about it.
The answer comes from why Breville introduced the Dual Wall portafilter at all.. the idea behind it is that it pressurises the basket then forces all the coffee out through a tiny nozzle, to then relax again and drip into the cup. its a fake internal bottom with its sole purpose to force coffee through a small hole, which in turn aerates the coffee. That aeration is what creates a foam like look to the extraction, which then mimics quality coffee with crema. The problem was that most of Breville's customers at the time were buying supermarket coffee, which was sometimes 12 or more months post roast (minimum 3 months), where the crema is dissipated after 6 weeks usually. This problem was compounded by companies like Lavazza who would leave their roasted coffee out to go stale before packaging it, so that the bags could be formed into bricks, and retain that shape during transit - wasted air means higher transport costs.
So, that's the reason the dual wall was invented, and it doesn't really cause a problem with fresh roasted coffee at all, except it creates an unnatural path for the water under pressure to flow through the puck - water will take the path of least resistance and so it will head for the middle and not so much the sides - will that result in a weaker coffee? Will that reduce the flavour of your coffee?
A traditional single walled filter allows a more natural path for your water to flow through the puck, and could mean your coffee tastes fuller. The only downside is if you are using coffee that is not fresh roasted, you will end up with a flat looking coffee. Its important to note that while double wall filters are intended to improve the look, they cant improve the flavour, and I think they can contribute to a decrease in flavour, both by the aeration process and the problem of water taking the shortest path and lastly by encouraging channeling of your coffee puck, like erosion on a dirt road.
As far as to answer how many grams of coffee should be used in a basket, the Italians traditionally used 7 grams per shot, so that's 7 grams in the single basket, and 14 grams in the double basket. They also tended to grind extra fine and tamp very lightly. As coffee has evolved, we tend to up-dose a little, so 8 (or even 9 grams) per shot. So that's 9 grams in a single and 18 grams in a double - the trick will be to grind a little coarser and also tamp a little harder with about 15kg of downward force. Its all an experiment! I usually only use a double filter, or triple filter paired with a bottomless portafilter handle. The bottomless is opening up an entirely new world of coffee technique and training - the main idea with a bottomless filter is as a training aid, so the user can determine by sight if there is any channeling in the coffee puck or unevenness in the coffee grounds distribution. It certainly looks pretty during extraction, so it adds to the aesthetic, but when a shot goes wrong, you can end up with a squirt of coffee shooting out at your business suit!
I hope this helps a little - let me know if I can explain anything in more detail.
That's a pretty advanced debate, it's a pretty small percentage of coffee lovers that care to think about it.
The answer comes from why Breville introduced the Dual Wall portafilter at all.. the idea behind it is that it pressurises the basket then forces all the coffee out through a tiny nozzle, to then relax again and drip into the cup. its a fake internal bottom with its sole purpose to force coffee through a small hole, which in turn aerates the coffee. That aeration is what creates a foam like look to the extraction, which then mimics quality coffee with crema. The problem was that most of Breville's customers at the time were buying supermarket coffee, which was sometimes 12 or more months post roast (minimum 3 months), where the crema is dissipated after 6 weeks usually. This problem was compounded by companies like Lavazza who would leave their roasted coffee out to go stale before packaging it, so that the bags could be formed into bricks, and retain that shape during transit - wasted air means higher transport costs.
So, that's the reason the dual wall was invented, and it doesn't really cause a problem with fresh roasted coffee at all, except it creates an unnatural path for the water under pressure to flow through the puck - water will take the path of least resistance and so it will head for the middle and not so much the sides - will that result in a weaker coffee? Will that reduce the flavour of your coffee?
A traditional single walled filter allows a more natural path for your water to flow through the puck, and could mean your coffee tastes fuller. The only downside is if you are using coffee that is not fresh roasted, you will end up with a flat looking coffee. Its important to note that while double wall filters are intended to improve the look, they cant improve the flavour, and I think they can contribute to a decrease in flavour, both by the aeration process and the problem of water taking the shortest path and lastly by encouraging channeling of your coffee puck, like erosion on a dirt road.
As far as to answer how many grams of coffee should be used in a basket, the Italians traditionally used 7 grams per shot, so that's 7 grams in the single basket, and 14 grams in the double basket. They also tended to grind extra fine and tamp very lightly. As coffee has evolved, we tend to up-dose a little, so 8 (or even 9 grams) per shot. So that's 9 grams in a single and 18 grams in a double - the trick will be to grind a little coarser and also tamp a little harder with about 15kg of downward force. Its all an experiment! I usually only use a double filter, or triple filter paired with a bottomless portafilter handle. The bottomless is opening up an entirely new world of coffee technique and training - the main idea with a bottomless filter is as a training aid, so the user can determine by sight if there is any channeling in the coffee puck or unevenness in the coffee grounds distribution. It certainly looks pretty during extraction, so it adds to the aesthetic, but when a shot goes wrong, you can end up with a squirt of coffee shooting out at your business suit!
I hope this helps a little - let me know if I can explain anything in more detail.
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