# Surprising variation between bean batches?



## Bica60s (Dec 3, 2019)

I recently bought a Rancilio Silvia and have watched numerous You Tube vids on the best methods for temperature surfing to attain the more consistent results. First few bean batches were fine, using a Sage Grinder Pro, dialling in until I had a delivery time of between 27 to 30 seconds for a 1:2 ratio coffee using 15gr of ground beans. The setting for the grinder was 8 (1 being the finest and 30 being the coarsest for the "fine" area of the settings) set for a 14.6 second grind time.

I usually follow the same routine which is switch on, pull water through to ensure there's enough on the boiler, and leave until the thermostat light extinguishes. I then push the brew button to flash off the steam until a smooth flow of hot water is attained (a few seconds) and place my tamped portafilter under the group-head and brew.

I clean the burrs between each bean batch of beans (250gr) ground and try and keep the method consistent.

I used a new batch of Lavazza Italiano Espresso this morning and using my grind setting of 8, the resultant brew was salty and poured through in just 12 seconds. I dialled the grinder down to 6 and had another go. Still just 15 seconds, with more crema this time but still salty and under infused. I dialled it down to 3, this time achieving a 25 second brew but with slightly less crema but a more balanced taste.

I don't understand how a day ago using the same beans, albeit from a different batch, the settings could be so much different. I've not had this before so wondered am I doing something obviously wrong?


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## MWJB (Feb 28, 2012)

I'm a bit conused by you reference to 15g dose (sounds a shade on the light side?) and to 14.6s grind time?

You're definitely grinding 15.0g into the PF each time, not relying on a timed dose?

Why are you aiming for 27-30s, you might be able to go longer in time without issue, time is a poor way to dial in (grind setting vs taste balance is more reliable).


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## Bica60s (Dec 3, 2019)

Yes, that's right. I set the grinder to achieve about 15gr which is my starting dose for most beans. Some I prefer to dose a little more, but for most varieties about 15gr seems about right for me. I usually do rely on taste, but just made the observation that for the first batch of beans of that variety, with the settings made, the taste was spot on and dose time about 30 seconds. The second lot was salty and poured through in less than half the time which to me indicates under infusion. It just got me a bit baffled as they were the same variety


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## MWJB (Feb 28, 2012)

Use scales to ensure coffee dose consistency. Otherwise you can't be sure how much variation is due to the new batch (shouldn't be the difference between normal & very low extraction), or down to changes in actual dose weight.


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## Squidgyblack (Nov 18, 2019)

Bica60s said:


> I don't understand how a day ago using the same beans, albeit from a different batch, the settings could be so much different. I've not had this before so wondered am I doing something obviously wrong?


 Likely to do with the age of the beans. The further past the roast date, the finer you'll have to grind. With beans like Lavazza, especially if they've no roast date, it's a wild guess at when they were roasted, they could have been sitting in the back of a warehouse for months before being put on the shelf.


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## Bica60s (Dec 3, 2019)

That's a very good point. So much for relying on keeping records so I can set each bean variety notes for the grinder! I'll just have to dial each new bag in and accept a loss of 45gr or so until I get it into the ballpark.


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## Bica60s (Dec 3, 2019)

MWJB said:


> Use scales to ensure coffee dose consistency. Otherwise you can't be sure how much variation is due to the new batch (shouldn't be the difference between normal & very low extraction), or down to changes in actual dose weight.


 I do.


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## ashcroc (Oct 28, 2016)

Bica60s said:


> That's a very good point. So much for relying on keeping records so I can set each bean variety notes for the grinder! I'll just have to dial each new bag in and accept a loss of 45gr or so until I get it into the ballpark.


Your notes will give you the ballpark. While there will undoubtedly be differences between batches, it shouldn't be that far out.


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## TomHughes (Dec 16, 2019)

You have a Silvia and running lavazza through it??? Sacrilege! Stump up for some proper beans man!


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## Bica60s (Dec 3, 2019)

TomHughes said:


> You have a Silvia and running lavazza through it??? Sacrilege! Stump up for some proper beans man!


 One man's meat...I use what I like. I couldn't care less what anyone thinks.


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## TomHughes (Dec 16, 2019)

Bica60s said:


> One man's meat...I use what I like. I couldn't care less what anyone thinks.


 I was only joking, but seriously, you're asking why you have inconsistent shots? It's because you're feeding your machine a stale old bean!

It's fine to like the lavazza flavour, hell, I love a bit of earthy robusta. And it's something missing in the British roaster repertoire I think because of the snobbery around robusta. But it does exist. see the rave Italian blend here -

https://ravecoffee.co.uk/collections/coffee-bean-blends/products/the-italian-job-blend?variant=3150416248858

Treat yourself to some nicely roasted beans this Christmas, pull your consistent shots on you're beautiful machine.

Otherwise you could sell me your Silvia and I'll send you over a Nespresso machine. ?


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## Bica60s (Dec 3, 2019)

Yes, sorry, my response was curt but not personally directed to you Tom. I was just making the point that if someone enjoys a particular bean flavour, then that's all that should matter to them.

Today, I re-tried my "normal" grinder settings for the old batch...and to confuse matters even more, it was spot on (again)! I emptied the hopper of the old, cleaned out the grinder and brewed some more of the newer batch using the exact same settings and weights and hey-presto, an identical flavour and good rich crema. I haven't the foggiest why several shots yesterday went all over the place as everything was controlled the same but something was obviously out.

For the record, Lavazza Italiano Espresso uses no Robusta (I don't especially like that variety). It's a100% Arabica blend.

Rave beans are just up the road from me in Cirencester so when I get the time, I'll jump on the bike and head over there to see what they have. The Lavazza that I buy is the only one they offer on the local supermarket shelves that I like and is not bad value at £4....I much prefer it to Illy for example which was one I had been using for a while. Over-priced though.


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