Post By flynnaus
Post By By6
I'm grinding my coffee fresh and the beans are also fresh. Grinder used: Breville Smart Grinder.
My problem is relatively early blonding. I notice blonding around the 23-25s mark and stop the extraction.
Is early blonding a sign of channeling or not grinding fine enough?
So we have something to go by, what sort of machine are you using, which beans, and when roasted?
In addition to Mal's questions, what has changed compared to before you noticed the blonding? Different beans perhaps?
How long have you had the grinder for and what quantity have you ground with it so far?
Most importantly, how does the coffee taste?
Breville Smart Grinder Pro - probably has gone thru 5 kg. Should be seasoned?
Using depressurized portafilter with the Saeco Poemia. Has always noticed blonding and lightening of flow before 30s. usually dosing 16.3-16.5 g. Using beans around 5 days after roasting. Light medium roast. Local roaster.
Coffee tastes ok if I stop at start of blonding but bitter if I do 30s count. just wondering about optimization.
The grinder should be fine. I thought that the burrs might be worn out.
Originally Posted by limms
Not familiar with your machine. What volume of coffee do you get from a 25 second pour? You could play around with different dosing and tamping but 25 seconds may be the limit of your machine?
What if you tried a slightly darker roast?
The Poemia is a small boiler machine, similar to the Via Venezia. As it is a small boiler, the temperature fluctuations during heating of the boiler can be significant.
The shot may be extracting at too high of a temperature which is common with these types of machines. I'm not entirely sure if this would cause early blonding but it's something to consider.
You will need to temperature surf the boiler to get the right temperature for extraction. Once the ready light has switched on, run some water through the group head without the portafilter in place and the water will probably be spitting and bubbling out. It should soon settle down to a steady stream.
It's trial and error as to when to start and stop the shot to get the optimum temperature but you certainly don't want to be extracting when the boiler has just reached the ready state as it will be too hot.
30 ml in 30 seconds is a general target for good taste.
If you're getting good taste at 25 seconds that sounds fine to me.
Sounds like the op is dosing a double (16g) so that's 30 mls per spout on a double, ie: 50-60mls in total from 16 grams of grounds.
Originally Posted by GregWormald
30 mls total would be a very tight ristretto which may not be what the op is trying for.
I have rigged a temperature probe on the boiler and have been pulling my shots at 93 degrees Celsius. Yes the boiler tends to be way too hot. I usually do quite a long flush to bring the temp down to 93 before pulling. This is especially so if I steam milk first. Refilling the boiler after this does not cool the boiler enough. I recognise that this temp won't reflect the actual water temp but it should be more consistent than blind surfing. If I dose 16g and pulling a 3:1 recipe, I should be extracting around 48-50g and I can get this in ~23s. The flow comes out ii 6s and is as close to a rat's tail as I can get. I guess this is as good as I get from this machine.
In terms of taste I would say it is still a tad bitter but the balance between acidity and bitterness is better if the coffee is cooler.
Firstly, I apologise if i'm making you 'suck eggs' by any of the following, as that is not my intent. Hopefully it's helpful -
Blonding primarily occurs as a result of a combination of the grind setting and the consequent flow rate (this early blonding is thus shot time related and most likely not what you're looking to solve). What I think you are looking to fix lies within the beans themselves (blonding resulting from trying to extract too much volume relative to the bean).
Beans will only allow an extraction of 'x' amount (effective yield). Different beans give different yields. The blonding colour occurs as the available dissolvable solids within the puck gradually reduce - the change in colour from start to finish being evidence of this process. Sudden blonding can be a result of channeling - but I don't think this is your issue, based on your description.
Your description would indicate that you have reached the limit of your beans yield (as 22 to 25 seconds is a very acceptable extraction time). In my fairly reasonable experience, trying different beans will give different results and if your yield isn't acceptable with these beans, consider moving onto another variety / origin. I have not found yield to be greatly influenced by temperature to any measurable degree.
I have roasted beans that will yield 40mls max from a 19gm basket (tasting sweet). An identical dose in the same machine at the same temperature with a different bean has yielded up to 60mls (also tasting very sweet). Some beans just have more to give than others.
Thx for the good points. i think what you have said is true. I bought a tds optical meter thingie. Perhaps it is time to use this to compare.