Extraction time for a single shot from a double basket

[hyoshidan]

I have been confused about extraction time for pulling a single shot from a double basket (20g).

I was taught that the extraction time for a single shot from a single basket should be 30 seconds. I was also taught that the extraction of 2 shots from a double basket should also have an extraction time of 30 seconds.

This being so, how long should a single shot from a double basket take for extraction?

I did a barista course earlier in the year and when I asked the trainer he did not answer, but rather told me off for wanting to use a double basket.

I heard today from a very knowledgeable man that he extracts a 30ml single shot from approx 22g of coffee in 30 seconds. In my 20g VST basket I have 30ml racing through in about 15 seconds, although my bar pressure looks fine (9 bar).

So, how do I go about pulling a single shot from a double basket?

[Barry O'Speedwagon]

Grind finer, up the dose, or cut the shot earlier

What exactly are you trying to make? A ristretto, or do you just want a very slow pouring shot? It's not clear what you are trying to achieve.

[hyoshidan]

I am trying to get a better 30ml shot. I really didn't like what I was getting from a single basket. I'm still after 30ml, so is that a double ristretto?

How do you go about a good single 30ml shot Barry O? (basket size? extraction time?)

[fg1972]

Hi hyoshidan,

Sounds like you're wanting to get a single sized serve from a double basket (double ristretto)
If you're getting 30ml in 15 seconds then you may need to,
grind finer
increase the dose
tamp harder
or a combination of the above
Hope this helps

[hyoshidan]

Thanks fg1972,
If I'm already at registering good pressure, wouldn't finer grind, increased dose or harder tamp start to choke the machine?

[Barry O'Speedwagon]

I am trying to get a better 30ml shot. I really didn't like what I was getting from a single basket. I'm still after 30ml, so is that a double ristretto?

How do you go about a good single 30ml shot Barry O? (basket size? extraction time?)

It depends on the bean, and the roast depth (and your taste). Firstly, I rarely try to make a 30ml shot (it's not obvious why that would be my objective). But I do tend to end up with approximately 40ml shots from a double basket. There's nothing peculiar about my technique. Set a dose that gives just a little clearance under the shower head. Adjust the grind til the stream blondes in about X seconds. Cut the shot when it blondes. Or a bit before if that suits your taste. I tend to prefer a slower extraction with about 35-40 seconds til the stream blondes, but that doesn't work for all beans and roast depths.

What is your normal procedure when dialling in a bean?

[herzog]

So, how do I go about pulling a single shot from a double basket?

A cup under each spout. Both cups will contain a single shot.

Throw one away.

[hyoshidan]

Thanks Barry O,

I'll have a go at reducing the gap between the dose and the shower head (more coffee).

By dialling in a bean, do you mean the grind?

[Barry O'Speedwagon]

By dialling in a bean, do you mean the grind?

Well, yes largely. I do sometimes adjust the dose slightly though.

[fg1972]

Thanks fg1972,
If I'm already at registering good pressure, wouldn't finer grind, increased dose or harder tamp start to choke the machine?

yes but it will slow down the extraction resulting in a less runny shot.
obviously if you extremely changed grind/dose/tamp the machine would literally choke but the key is one minor adjustment at a time then observe/taste the outcome.

[_moby_]

Thanks fg1972,
If I'm already at registering good pressure, wouldn't finer grind, increased dose or harder tamp start to choke the machine?

No, grinding finer will lengthen the extraction time and you’ll get a better shot (up to a point obviously). If you are getting 30ml in 15 secs from 22g then the shots are almost certainly under extracted.

What you are looking for is almost exactly what I make at home. I use 22-23g of ground coffee in the basket and aim for 30g in the cup (I go by weight not volume). I’ve found the best extraction time to be around 35 seconds.

The best idea is to fix your dose (22g if that is what you want) then aim to get the amount you want in the cup and adjust the grind to get the best extraction. You’ll be able to taste the difference between a 15, 20, 25, 30, 35, 40 second shot time to get the same amount in the cup from the same dose.

[hyoshidan]

I think that maybe I need to place less importance on the pressure gauge reading.

[Rolf]

double basket:
double portafilter with double basket = 2 cups in 25 sec for about 25 to 30 ml
single portafilter with double basket = 1 cup in 25 sec. for about 25 to 30 ml.
to get that you have to adjust the grinding finer or the othe way, but both time with the same amount of coffee.

I just made a try (a) double portafilter with double basket and a (b) bottomless portafilter, both times the same amount of coffee and the same grinding... and it did work nearly perfect,
a = 25 sec. 30 ml in two cups
b = 25 sec. 25 ml in one cup
a did taste better, but irrespective I also could drink the b-cup

[chokkidog]

Your learned friend ;-) has put you in the ball park with a base line for you to start experimenting.

30ml-30 secs is a good place to start but with some coffee I've had great extractions at 35 secs and even some at 40 secs.

Don't be bound by rules (they are meant to be broken) but by what you like to drink. Different coffees will behave differently, so be flexible.

Saying that tho' I have rarely had a decent coffee from a sub 25 sec pour.