# VST basket 15 or 18 thermal issue?



## GrahamS (Aug 27, 2015)

I know the 20 and 22 require a bottomless portafilter, which I don't have yet, just wondering as the 18 will require at least 6g more water is there a noticable difference in water temp during the shot - and does that mean the 18 - 20 - 22 make progressively larger but worse servings?

as the machine is designed for 14g does it mean the 15 is the best vst upgrade?


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## foundrycoffeeroasters.com (Jun 19, 2014)

Why would the 18g basket need 6g more water?


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## Mrboots2u (May 10, 2013)

I'm lost - what machine is designed for 14g? No shots don't get worse the bigger the basket . Intra shot temp will be a function of your machine not the basket


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## h1udd (Sep 1, 2015)

To keep a 1:2 ratio

15g:30g

18g:36g

6g more ... Although in reality it's probably 7-8g more accounting for water held in puck


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## Mrboots2u (May 10, 2013)

Ok but what modern machine is " designed for 14g" 14 g is just old Italian dose to a double shot ... Not what machines are based on ?


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## h1udd (Sep 1, 2015)

I think the op is worried that temp stability will change more for 36g water over 30g


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## jeebsy (May 5, 2013)

Just shoot the extra 6g out the hot water dispenser


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## Xpenno (Nov 12, 2012)

If your machine can only deliver 30g of hot water then you might need an upgrade :S


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## risky (May 11, 2015)

jeebsy said:


> Just shoot the extra 6g out the hot water dispenser


It's called the Steam wand, weren't you paying attention?


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## Missy (Mar 9, 2016)

When is larger ever worser?! ?

I got really confused by gaggias "14g" basket. Took me a couple of goes to realise 14g is nowhere near enough for a decent shot.


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## foundrycoffeeroasters.com (Jun 19, 2014)

Missy said:


> When is larger ever worser?!
> 
> I got really confused by gaggias "14g" basket. Took me a couple of goes to realise 14g is nowhere near enough for a decent shot.


We routinely use 15g doses for lever shots, works out great most of the time.


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## foundrycoffeeroasters.com (Jun 19, 2014)

If I could work out how to do it, I'd point the op to the excellent brew ratio introductory posts on here.....there may be revelations on the horizon.


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## GrahamS (Aug 27, 2015)

gaggia classic - which doesn't have a huge boiler, and i know shot temp reduces as the shot is pulled, due to cold water entering, so naturally the larger the shot, the greater the dip.

i seem to have a habbit of asking questions that lead to more questions.


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## Missy (Mar 9, 2016)

Is that where a PID comes into its own? Or am I totally lost?


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## GrahamS (Aug 27, 2015)

Missy said:


> Is that where a PID comes into its own? Or am I totally lost?


pid would hold the hot temp at a much tighter range, and when cold water is introduced it 'should' react quicker than the thermostat


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## GrahamS (Aug 27, 2015)

foundrycoffeeroasters.com said:


> If I could work out how to do it, I'd point the op to the excellent brew ratio introductory posts on here.....there may be revelations on the horizon.


http://coffeeforums.co.uk/showthread.php?22879-Beginners-Reading-Weighing-Espresso-Brew-Ratios


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## foundrycoffeeroasters.com (Jun 19, 2014)

GrahamS said:


> gaggia classic - which doesn't have a huge boiler, and i know shot temp reduces as the shot is pulled, due to cold water entering, so naturally the larger the shot, the greater the dip.
> 
> i seem to have a habbit of asking questions that lead to more questions.


The boiler is plenty big enough to pull long shots. If anything, I would have thought that a small single boiler machine is likely to be pretty stable, given that all the water in the boiler is at the same temp.


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## Dallah (Jan 31, 2015)

foundrycoffeeroasters.com said:


> We routinely use 15g doses for lever shots, works out great most of the time.


15g for a double? Hmmm. Maybe the Italians know what they are talking about when a lever is involved


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## El carajillo (Mar 16, 2013)

When I tried using a 21 gm basket with the Classic it did deteriorate the shot, I put this down to the size of the boiler and the mixing of the incoming cold water lowering the temperature of the water already in the boiler. With larger machines with larger boilers the effect would not be noticeable.

I did not have a P.I.D. on my Classic but I imagine it would be a big improvement ( sensing the incoming cold water and switching immediately unlike a thermostat lagging behind)


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## mathof (Mar 24, 2012)

Dallah said:


> 15g for a double? Hmmm. Maybe the Italians know what they are talking about when a lever is involved


I routinely make 7g singles in an LM Strada basket and 15g doubles (and split 7g shots) in a 15g VST basket. Very Italian, I believe, and very satisfying.

Matt


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## Jumbo Ratty (Jan 12, 2015)

GrahamS said:


> I know the 20 and 22 require a bottomless portafilter, which I don't have yet, just wondering as the 18 will require at least 6g more water is there a noticable difference in water temp during the shot - and does that mean the 18 - 20 - 22 make progressively larger but worse servings?
> 
> as the machine is designed for 14g does it mean the 15 is the best vst upgrade?


I have a 15g VST for my gaggia classic and I have found 17.5g works best for me in it, not sure why its said they are + - 1g either way ?

At 18g in the 15g basket I start to get the imprint of the shower screen on the puck after pulling the shot.

Also, this graph might help with the temp drop conundrum

Bare in mind this is with 60ml of water going through the group


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## risky (May 11, 2015)

Jumbo Ratty said:


> I have a 15g VST for my gaggia classic and I have found 17.5g works best for me in it, not sure why its said they are + - 1g either way ?
> 
> At 18g in the 15g basket I start to get the imprint of the shower screen on the puck after pulling the shot.
> 
> ...


Obviously it differs depending on what beans you are using. Yours seems to occupy a very low volume in the basket.

Just remember that graph is not indicative of all classics. If you want to see what yours is like you can get a probe system for £15 on eBay and drill a spare basket.


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