Hi everyone,

newbie here that is looking for some advice. Like many newbies, I am using a rancilio silvia and rocky. I've been trying to "dial in" my equipment, and I've been reading up on brew ratios a lot. I love the idea of using dry weight/shot weight to measure pulls as an extraction %. Seems to make sense. Whether or not these are the accepted values, I've been using the following ratios, originally posted by Andy, as a comparison:
60-140% Ristretto
40-60% Normale
27-40 % Lungo

I've also read many suggestions that, although this is a good way to discuss espresso, other variables like time need to be considered. With all of this in mind, I set out to test my equipment and collect some data. I used a digital scale to take all weight measurements, and I temperature surfed the silvia by expelling steam from the group immediately upon the light turning off and then counting 4-one thousand. I used a La Marzzoco double basket (not ridge-less). My intention was to manipulate 1 variable at time. I figured grind setting should be first. So most of these data are based on 18g in the double basket. I did however, varying the dosage on a few trials. All shots were pulled for exactly 25 seconds, and I applied 30lbs of tamp pressure via bathroom scale. I used a double spout portafilter for all. Here is the data, and the variables reading from left to right are:

Grind Setting dry weight shot weight approx. vol brew ratio


2 14g 35g 1.0 oz 40%
3 18g 19g 0.75 oz 94%
3 18g 20g 0.75 oz 90%
4 14g 62g 2.0 oz 22%
4 14g 61g 2.0 oz 23%
4 18g 32g 1.0 oz 56%
4 18g 34g 1.0 oz 53%
5 18g 47g 1.5 oz 38%
5 18g 53g 1.75 oz 34%
5 20g 29g 1.0 oz 69%
6 18g 53g 1.8 oz 34%
6 18g 58g 2.0 oz 31%

Well, I was certainly surprised. My goal was to pull normal double shots, and all of my 2.0 oz shots resulted in very low brew ratios. I was hoping to work out the grind settings so that I could consistently get 2.0 oz pulls in the 50-70% ratio. Doesn't look like I am close to that. The only thing I can think of is to load up even more initial dosage weight, but the double basket doesn't hold more than 20 grams. It's not to say all of these shots tasted bad (the low extraction ratio ones did though). I'm also trying to "dial in" my taste buds as well. Based on what I tasted (on this round), and extraction ration of 50-70% seems ideal to me. But how can I get 2 ounces??

I would appreciate any advice from some experienced members. This is a small sample size, and it is possible I'm interpreting my numbers wrong. However, if I was to simply follow the standard rules of pulling a shot:

14-18grams of espresso, tamp with 30lbs of pressure, pull shots for approximately 25 seconds, collect approximately 1.5-2ozs of liquid,

then ALL of my shots would have an extraction ratio below 40%, and these don't taste very good to me.

Thanks

Grind finer.

The flow rate is too fast. You can increase the dose to slow it down, but Silvia needs a fair amount of head space so I wouldn't go that route. Flow rate is influenced by the basket, and I'm not sure the LM Double is a good choice for Silvia. Maybe you should try it with the stock basket, but that will probably limit you to 14g dose.

In any case, you're best bet is to grind finer.

I would forget about the volume for now. It's too difficult to consistently target a particular volume level because the crema varies from one coffee to another, and with the same coffee if as it ages. Shot weight is a much more precise and repeatable target.

DanseMacabre, as a general rule a 2oz pull weighs 60grams..I you always want a 2oz double you would need at least 30g in the portafilter to get your 50% brew ratio...That's a big portafilter:-)

ghostchili wrote:DanseMacabre, as a general rule a 2oz pull weighs 60grams..

This is incorrect. 2oz (volume) of water weighs 60g. 2oz (volume) of crema weighs about half that.

DanseMacabre wrote:My goal was to pull normal double shots, and all of my 2.0 oz shots resulted in very low brew ratios. I was hoping to work out the grind settings so that I could consistently get 2.0 oz pulls in the 50-70% ratio.

Honestly, I don't see how you can get a 70% brew ratio out of a 2oz (volume) extraction. 50% is a reasonable goal.

I routinely pull doubles on my Spaz S1, using 15-16g doses and extracting ~45ml volume (1.5oz).* The resulting shot weight is ~22g, for a brew ratio of ~70%. A volume of 60ml (2.0oz) would reduce the brew ratio to about 50%.

One problem with your posted data is consistency. Your extracted weights and volumes are all over the map for a given dose. For example, you have 18g doses with extraction weights ranging from 19g to 58g, a 3X variation. This is really troublesome, and suggests puck prep issues such as channeling. I concur with those who suggest that you need to grind finer. I further recommend lower doses (e.g. 16g) and working on improving your consistency. And of course you need to be using high quality, freshly roasted coffee, or all this data is meaningless.

* Note that 1.5oz is volume, not weight. My pours are virtually 100% crema, which is why they weigh 22g rather than 45g.

Also remember that every blend or SO is different. What you are using may not work well pulled in the normal range. Adjust by taste then when you find what you like for that particular coffee make note of the brew ratio so you can go back to those settings as you go from blend to blend. It also helps when discussing a coffee since some machines may not be able to take those high doses. You can use a lower dose but still pull the same ratio for a comparable shot.