Why the difference in pulling singles to pulling doubles?

I have a 2 grp Nuova Simonelli Aurelia in my laundry room set up so I can practice on it while I am waiting for the go ahead on my coffee shop in the Caribbean. When going from single shot basket to double I have to change the grind on my MDX grinder in order to get the shot to work. I have to make it coarser for the single and the finer for the double. Is this a typical thing or can something be done. I am sure I will be pulling mostly doubles but in order to try and keep waste to a minimum, if I only need a single shot then why not pull a single. If I have some ground espresso already in the grinder then it is too fine to pull the single and would have to get rid of that to then grind coarser and then lose the idea of saving on waste.

Any ideas

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Heres a thought. Correct me if i'm wrong...

When brweing an espresso in a double basket, you will always be dealing with a set amount of room. How much coffee is in that room is up to you, but the space is always going to be the same. The single baskets, however, hold an entirely diffrent amount of coffee (usually 9 grams). The change in space will account for a change in how the coffee will react with the pressure put on it.

Think of it this way. Imagine you have 2 buckets, a small one and a large one. If you fill them both with water, the small one will obviously become full first.

Keep in mind that although we are only working with a diffrence in space, you also must take into account all your variables. Pressure, and the way it reacts with the coffee, will change drasticly during the pre-infusion cycle of your brew. This occours because the solid, packed coffee slowly becomes saturated, resulting in an ever changing "space" that you are dealing with. When the water breaks through the bottom of the packed coffee, you reach a standardized pressure. If your machine is pressure stable, the actual pressure on the coffee shouldn't change any more from here.

Bear with me for just another paragraph or two...

When a substance is under a changing pressure, the way it reacts with temperatue also will be extremly variable. This will also standerdize when the water breaks through the packed coffee.

This will all happen sooner with a single basket than with a double basket. There is less room to pressurize, therefore the coffee will react diffrently with the change in presssure/temperature. Make sense?

It is deffinitly too early to be thinking in terms of science. Ima go get me some coffee.
I do understand the physics of it, I am just asking if this is then the case, do I need to get another grinder? One for double shots of espresso, one for single shots and one for decaf. Or maybe get a fourth for single shots of decaf. I know that I could just pull doubles all day long and only need to adjust the grinder as the day goes on, but the need to adjust the grinder when going from double to single seems like it should not be needed.

I believe that the basket shape is to keep the depth of the coffee the same from single to double, so the coarseness of the coffee should then allow a smaller volume of water to pass through a smaller volume of coffee at about the same rate as a larger volume of water to pass through a larger volume of coffee.

Barry
I work on a three-group Aurelia, and it takes a different distribution technique for singles. When using the double basket, my finger is straight, but when swiping with a single, you need to arch your finger downwards in a sort of concave shape. I believe a better designed basket could solve this problem, but it's completely workable, and I get excellent single shots, and in my experience, once you get the feel of them, they're a lot more consistent.
Barry, I have the same issue with 2 different machines. One is a La Cimbali M22 (2 group Semi-Auto), and the other is a Rancilio Epoca, also a 2 group Semi-Auto. If my grinde is adjusted well for the double, then the single comes out agonizingly slow-- a slow drip.

I've tried 2 techniques. One is to use less pressure when tamping the single.
The other is what Pete suggested-- arching the finger so you have less coffee in the filter.
I think the latter may be the better way.
You can always pull doubles and if you have an extra shot you put it in a container in the fridge to use with coffee based blender drinks. There are so many flavors going on in a sweet dairy based blender drink it's hard to taste the difference. Just start fresh each day.
I will be using a Filtron cold coffee brew for iced and blended coffee drinks. I was just looking for a simple answer to help and conserve waste. Since I will be in the Caribbean, everything comes in by boat and I was just looking to help control costs.

Barry
Matthews post has some value here.

Also think about the physics here, if your using a machine that's got an e61 group, then you load a portafilter in it with a single basket that is overdosed to 9grams, your essentially taking 9bars of pressure and applying it to a funnel of tamped coffee..... wide on top of grind bed and narrow on bottom of grind bed, ... examine how the basket looks.

OK, so if its a funnel shape that means there is physically more coffee per sq cm in the center when compared to the sides..... it equals over extraction on the sides resulting in a inconsistent espresso. Water travels the path of least resistance.

Maybe some things were just meant to be doubles, ... its not a bad thing. Singles could be done, but I think the grouphead would have to be modified to be narrower, allowing a deeper single basket.

Also, with regards to your grinder, approach your grinder usage as your hands being the only variable, you should be able to lock your grind with only seeing one pull from your 1st dose, ... practice, every movement should have a reason, ... then,,,,, no waste
Simple solution....Charge for the double. Then it is not you wasting the shot it would be your customer. Either way you are getting the cost investment out of it. The other option would be to put two grinders on the bar. One for singles and one for doubles but that would be a lot of coffee to pull off the initial investment. In my opinion the always double method has worked well. Your barista will be trained to pull the same shot over and over again and will know it is their mistake if the coffee is off and not be able to blame it on the basket. Good luck in the Caribbean and let me know if you need a temp barista.
Unfortunately I don't think I will be able to participate in the "Barista Exchange" program, the fine for having a non local working without a work permit is 100,000naf or Antillean Guilders (about $57,000) first offense and the possible loss of business permit. Of course with a fine like that, that would be the end of the business.

Brian Davey said:
Simple solution....Charge for the double. Then it is not you wasting the shot it would be your customer. Either way you are getting the cost investment out of it. The other option would be to put two grinders on the bar. One for singles and one for doubles but that would be a lot of coffee to pull off the initial investment. In my opinion the always double method has worked well. Your barista will be trained to pull the same shot over and over again and will know it is their mistake if the coffee is off and not be able to blame it on the basket. Good luck in the Caribbean and let me know if you need a temp barista.
Now I wouldn't want that. Maybe just a visiting friend then. No money. Just an excuse to come out.

Barry Baker said:
Unfortunately I don't think I will be able to participate in the "Barista Exchange" program, the fine for having a non local working without a work permit is 100,000naf or Antillean Guilders (about $57,000) first offense and the possible loss of business permit. Of course with a fine like that, that would be the end of the business.

I am also a scuba instructor so maybe we can go for a dive and have an espresso while relaxing afterward. That sounds good.

Barry

Brian Davey said:
Now I wouldn't want that. Maybe just a visiting friend then. No money. Just an excuse to come out.

Barry Baker said:
Unfortunately I don't think I will be able to participate in the "Barista Exchange" program, the fine for having a non local working without a work permit is 100,000naf or Antillean Guilders (about $57,000) first offense and the possible loss of business permit. Of course with a fine like that, that would be the end of the business.

Most traditional shops actually don't use single baskets. They work solely on 14 gram baskets. Rather than pulling a single for an 8oz. or 12oz. pull a ristretto. I know what you mean about waste but in my opinion it tastes so much greater. And I have never been able to keep the same consistancy by switching different sized baskets.

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