Grind Vs Taste?

[CaptainDan]

Hello All,
I have been trawling through the topics in attempt to find an answer to my predicament but to no avail. I recently purchased a Silvia and a doserless Rocky. I have PIDed the Silvia and got myself an Espro tamper in attempt to reduce the variables in my search for the consistent shot. I currently have the thermostat of the PID set on 228 deg F.

I have been trying to dial in the grind setting on the rocky so that I can extract the correct volume in the right amount of time - 25-30s . From what I have experienced, being just a little too fine will give me a terribly bitter and cloying shot. Does this sound right? I thought perhaps the water temp may have been too high so dropped it to 222 deg, but all this resulted in was a tepid, bitter shot.

I have been using the Rancilio double basket, filling to overflowing them levelling and tamping to try to ensure the same measure each time. After tamping the level of coffee seems to coincide with the indented portion of the basket. When I remove the portafilter after the shot the puck has the mark of the nut from the bottom of the screen and a little moisture that quickly disappears and the puck has a slight give but holds together when ejected.

I am stopping the flow when the shot goes to a light tan colour and starts to look like a liquid rather than foam. My question is whether a couple of notches on the Rocky can make such a large difference to taste (from bitter and undrinkable to quite smooth) or is it some other variable that may be affecting the shot?

Any thoughts would be greatly appreciated!
Thanks,
Dan

[Dimal]

Re: Grind Vs Taste?

Hi CD,

I guess first up, what type of coffee are you using? Is it freshly roasted sourced locally or home roasted, for example?

Have you or someone else, adjusted the Silvias Over Pressure Valve to provide a 9 Bar pressure at the puck? Some of what you describe indicates that perhaps this has not been done. Silvias OPV can be factory set to 12 Bar or higher and this will severely effect the quality of shot that you are able to produce.

Your PID setpoint of 228deg F sounds pretty close and I would leave it at that for the time being.... no use introducing more variables into the mix. Everything else you describe about your technique sounds reasonable. There are other techniques you can try re: dosing and tamping, etc but the method youre using now is in the ballpark.

Freshly roasted coffee is essential to achieving quality shots and if the Brew Pressure is too high, you can end up with the results youre describing so I would address these two items first before going on with anything else. All the best,

Mal.

[CaptainDan]

Re: Grind Vs Taste?

Thanks for the response Mal,
I have had the problem with two different sorts of beans bought from specialty coffee shops - only a few days old and freshly ground just prior to going into the portafilter. I will have a look at adjusting the OPV and get back to you...
Regards,
CD

[MattG]

Re: Grind Vs Taste?

Hello All,
I have been trawling through the topics in attempt to find an answer to my predicament but to no avail. I recently purchased a Silvia and a doserless Rocky. I have PIDed the Silvia and got myself an Espro tamper in attempt to reduce the variables in my search for the consistent shot. I currently have the thermostat of the PID set on 228 deg F.

I have been trying to dial in the grind setting on the rocky so that I can extract the correct volume in the right amount of time - 25-30s . From what I have experienced, being just a little too fine will give me a terribly bitter and cloying shot. Does this sound right? I thought perhaps the water temp may have been too high so dropped it to 222 deg, but all this resulted in was a tepid, bitter shot.

I have been using the Rancilio double basket, filling to overflowing them levelling and tamping to try to ensure the same measure each time. After tamping the level of coffee seems to coincide with the indented portion of the basket.  When I remove the portafilter after the shot the puck has the mark of the nut from the bottom of the screen and a little moisture that quickly disappears and the puck has a slight give but holds together when ejected.

I am stopping the flow when the shot goes to a light tan colour and starts to look like a liquid rather than foam. My question is whether a couple of notches on the Rocky can make such a large difference to taste (from bitter and undrinkable to quite smooth) or is it some other variable that may be affecting the shot?

Any thoughts would be greatly appreciated!
Thanks,
Dan

I believe Allen Frew found a difference of about 9 seconds in the pour when changing a single notch on the Rocky (but dont quote me). The answer is yes a couple of notches can make a large difference to taste. The comment about the shot being bitter sounds like your brew temperature is too high. Im not a PID expert, but Im assuming the 222-228 degrees setpoint is the boiler temperature. Do you know what this translates to in terms of brew temperature? The literature suggests brew temperatures between 185 - 203, but most blends I play with prefer brew temperatures between 198 and 203.

One of the major things I found improved my shots on the Silvia (other than upgrading to a Mazzer) was updosing every shot. If you are using the standard OPV then the brew pressure could possibly be higher than 12 bar.

[CaptainDan]

Re: Grind Vs Taste?

Hi Matthew,
The times you quoted seem about right to me. Having looked into adjusting the pressure output of the Silvia, I am loathe to start playing around with the pressure just yet.... is this a common mod with Silvias?

Interesting what you say about the dose size - before I started trying to standardise everything, I used to just pile up the coffee in the portafilter as it came out of the grinder and tamp it. Now I think of it, I never noticed a really bad shot....just differnet volumes - maybe a bit more coffee is what is required - amazing that such a small difference can have such an effect!

I have read that 228 degrees (at the boiler cold water inlet) is meant to deliver water to the brew head at 205 degrees. I must say that in doing my experimentation, I did not notice a big difference in taste with temperature (also tried 226 deg and 222 deg) - but I did notice a definite difference in the temp of the shot when tasting it.

One other thing that has been bothering me - I was concerned that the first part of the shot may be steam - burning the brew - but every time I pull a blank shot it just seems to be water straight off. What I do notice though, is that if I turn on the hot water pump and open the steam knob, the initial delivery is quite steamy then turns to water. I noticed this when tuning the overshoot of the PID when recovering after a shot. Does this happen with your machine as well?

CD

[CaptainDan]

Re: Grind Vs Taste?

Hi,
One more thought for the experts. I have been taking the beans straight out of the fridge, grinding them then extracting. Could the fact that the coffee is cold have anything to do with the bitterness - i.e. exacerbating the heat shock as the water hits? Just managed to get a decent shot with some new beans that were at room temperature....

CD

[hazbean]

Re: Grind Vs Taste?

Frig is not recommended. Moisture, odours etc. See e.g.

http://www.ineedcoffee.com/99/07/storage/

As airtight as poss at room temp is best. We use old coffee tins,
preserving jars etc. Would like to find out where to get the bags with
valves that roasters use ....

[bruce_]

Re: Grind Vs Taste?

http://www.coffeeparts.com/coffeebags/bags.html

You can buy as few/many as you like.

I bought around a dozen or so bags. Enough for a number of different SOs and a few more bags so that I can try various blends. Also doesnt hurt to have a few more for those friends that "borrow" some fresh stuff...