# Extraction flavor issues



## craftygeek (Feb 19, 2014)

I'm still learning how to balance grind, tamp, bean weight & shot volume. I know i'm currently not getting it right either.

I have a few different beans to hand & have tried a few more over the last few weeks since I have had my Classic & SM90.

Dark roasts seem to be behaving themselves pretty well - while they aren't my preferred choice, I am getting them to make an americano that i'm happy with.

The problem seems to exclusively exist with lighter medium roasts...this has happened with 3 different beans now.

When pouring a shot, no matter if I pour what I think is the correct volume (starting to blonde) or over extract - I often end up with an overpowering vinegar sour taste. This has been more pronounced in a couple of the beans, but the sour flavor has been identical in each case which leads me to think that its a technical issue rather than the beans.

Using the double basket, i've been using 16g coffee - the darker roasts fill the basket at this weight, but the most recent lighter roast underfills it (next pull will be 17g).

Shot time is normally pretty good & i'm hitting 25-28 seconds when dialed in. Previously I was aiming to pour 2oz, now i'm looking for blonding & stopping (~1-1.5oz).

I have tasted the water directly from the group - it tastes fine, no sourness.

I also suspect that it the OPV is set too high & needs to be lowered - i'm on the waiting list for one of the pressure gauges doing the rounds so I can check.

So, this morning as an experiment, I used a dial milk thermometer in a poly cup to measure the temperature of the water coming from the machine (no portafilter). Machine had been on for a good couple of hours at this stage - temp ~87c. Then left it a couple of minutes, dumped water to trigger heating cycle - waited for the light to come on & tried again...~75c.

It would appear that my temperature is running a lot lower than it should be. Could this be responsible for such a noticeable issue?

Any opinions on the best way forward from here?


----------



## Mrboots2u (May 10, 2013)

hello

try weighing your dose and extractions

Use scales what can measure by 0.1g

Say put 16 g in and aim for an output weight as opposed to volume .

a 1.6 times extraction is a good place to start 16g in 24-26 g out in 25-27 seconds ish. ( from when you turn the pump on )

How does this taste? Don't worry about whether its 1oz or 2 oz's

Give it ago

Let us know if this helps


----------



## craftygeek (Feb 19, 2014)

Ok - I've just given that a go.

Temp surfed then...

16g in, stopped at 26.6g in 25s. Pretty close for a first attempt.

Flavor is improved, but the vinegar sourness is still there - although not as pronounced & is more acceptable.

I'm left with chocolate on my palate rather than vinegar now - a step in the right direction.


----------



## Mrboots2u (May 10, 2013)

craftygeek said:


> Ok - I've just given that a go.
> 
> Temp surfed then...
> 
> ...


Ok are you using a naked pf . this allows you to see if your distribution and prep is causing "channeling " which would give some sourness.

Ok now try letting it run a little linger and go for 16g say 28-30g out in 25-30 seconds .

How does this taste now ?


----------



## craftygeek (Feb 19, 2014)

I'm using the standard portafilter at the moment - a naked pf is on the wishlist.

Temp surfed then...

16g in, 29.5 out in about 35s - tamp was a tad too hard.

That was pretty disgusting - vinegar sour was more pronounced but gave way into bitterness. Left with bitter sour palate.

So looks like over extraction could be partly to blame?


----------



## The Systemic Kid (Nov 23, 2012)

35secs for your extraction is a little long. The temp figures you give above, if accurate, are well under the ideal extraction temp which should be around 93c + or - a couple of degrees. Low brew temp gives sourness.


----------



## gman147 (Jul 7, 2012)

Beans roast date? And where from?


----------



## garydyke1 (Mar 9, 2011)

I would say a combination of temperature & technique. Under 90C and you'd be getting some very bland potentially sour espresso.

Humour me :

Try grinding a little finer and running a shot for 40 seconds, aiming for output weight to be double the input . Try 17 into 34g.

Let us know how it tastes


----------



## craftygeek (Feb 19, 2014)

I've just done a couple more tests - going down as far as 16g in 24g out still has a lot of sourness going on.

I'm thinking its probably temperature related.

These current beans are Rwanda BUF Remera from Smokey Barn, roast date is 18th March (6 days rested)...picked up from their cafe/shop - they're not on the site yet.


----------



## craftygeek (Feb 19, 2014)

garydyke1 said:


> Humour me :
> 
> Try grinding a little finer and running a shot for 40 seconds, aiming for output weight to be double the input . Try 17 into 34g.
> 
> Let us know how it tastes


Ok...

Temp surfed then...

17g in 35g out in 45s (not spot on I know)

Still has the sourness...but other flavors do seem to have opened up that weren't there before - more deep savory (not bitter) than rounded chocolate now.

Crema also had some larger bubbles in it that weren't there before.

I don't think I can drink anymore coffee today now - buzzing a little too much









I also think there is room for improvement in my distribution and tamping technique...these beans grind to a lower volume which makes it harder to distribute evenly - but even when I get this spot on, I still have sour issues.


----------



## The Systemic Kid (Nov 23, 2012)

Do the beans produce a bigger than usual crema? I've got some Rwandan beans (not Smokey Barn) and they require 18 days resting. Yours may need longer than six days.


----------



## craftygeek (Feb 19, 2014)

The Systemic Kid said:


> Do the beans produce a bigger than usual crema? I've got some Rwandan beans (not Smokey Barn) and they require 18 days resting. Yours may need longer than six days.


No crema is fine & controlled - When I bought the beans on Friday, Smokey Barn said leave them a couple more days & that Sunday (ie, today) should be fine for them.

This is an issue that i've had using other beans as well...the issue is more fundamental than just the beans I think.


----------



## craftygeek (Feb 19, 2014)

I've ordered a new brew thermostat - i'll try to get that fitted next weekend & see if that makes a difference.


----------



## Dylan (Dec 5, 2011)

A milk thermometer in a cup is a horribly inaccurate way of measuring the temperature of the brew water, It's exactly the method I first tried using and got similar temp readings, I bought a cheap k-type thermometer from ebay to measure the temperature as it left the group head and found it to be in the correct range.


----------



## craftygeek (Feb 19, 2014)

I appreciate that its not the most accurate way of measuring - but we are talking about a 10 year old machine, so I think its best to rule it out as a cause.


----------



## Dylan (Dec 5, 2011)

craftygeek said:


> I appreciate that its not the most accurate way of measuring - but we are talking about a 10 year old machine, so I think its best to rule it out as a cause.


Do you mean to say not rule it out as a cause?

In which case I would completely agree, temperature is one of the first things to look for when getting a sour shot. Its just worth being very aware that there can be a significant temperature decline from group-head to cup.


----------



## DavecUK (Aug 6, 2013)

I read through and rather than quote just going to pick bits out from various posts.

1. You said you measured the temp in a polystyrene cup, what you got sounds about right for 92+ at the coffee.

2. How light are these Rawandan beans, do you have a photo especially good would be a comparison with beans you don't find sour.

3. Are there any other flavour notes with the sour e.g. slightly nutty/malty


----------



## craftygeek (Feb 19, 2014)

D_Evans said:


> Do you mean to say not rule it out as a cause?
> 
> In which case I would completely agree, temperature is one of the first things to look for when getting a sour shot. Its just worth being very aware that there can be a significant temperature decline from group-head to cup.


Possibly wasn't clear enough - I meant by replacing the thermostat it will rule that out as a possible cause.


----------



## craftygeek (Feb 19, 2014)

DavecUK said:


> I read through and rather than quote just going to pick bits out from various posts.
> 
> 1. You said you measured the temp in a polystyrene cup, what you got sounds about right for 92+ at the coffee.
> 
> ...


1 - I still think that the temperature could be partly to blame - but we should find out when I replace the thermostat.

2 - I don't have a photo handy, but can easily sort one out. The thing to remember here is that we're not just talking about a single bean...this is the 3rd bean that I've had the same issue with. The only connecting factor is that they were all from Smokey Barn, but having tasted 2 of his espresso's in house - they have none of that flavor at all.

The other 2 beans were the Sumatra Wahana Natural & the Kenya Ndimaini AA - both bought in house before the sale.

I can get some beans from another roaster locally that i'm more familiar with, but was hoping to try & get to the bottom of this before shelling out £6+ on another 250g to make more vinegar 

3 - yes there are some other flavours in there, chocolate & some nuts - but on the whole the vinegar sour overpowers it. Some of my results yesterday were improvements - I think that most users on here would class most of the shots as undrinkable.


----------



## Dylan (Dec 5, 2011)

You can try over-heating the water by turning on the steam for a bit, see if it changes the flavour in the cup.


----------



## craftygeek (Feb 19, 2014)

D_Evans said:


> You can try over-heating the water by turning on the steam for a bit, see if it changes the flavour in the cup.


Ah - that hadn't occurred to me, might try that in the morning if i'm with it enough


----------



## Edwin (Feb 20, 2011)

If you read through a variety of forum postings, you'll discover that lots of people (including myself) have been in the same position as you.

I've come to the conclusion that we just have different sensitivities when it comes to acidity in coffee. For some, a lack of what others experience as a powerful hit of lemon juice just tastes bland. They crave "fruitiness" in their espresso; in fact any mention of fruit in the tasting notes rings alarm bells for me.

I recently enjoyed a bag of Rave's mightily fine Monsooned Malabar, but have since got through half a bag of Brazilian Fazenda Ouro Verde Acai without producing anything remotely drinkable. What emerges completely lacks the "creamy sweetness" that's described. It's just sour, regardless of what I do with it.


----------



## craftygeek (Feb 19, 2014)

A minor update.

I let the beans rest a few more days - that helped, loads moredepth & nuttyness came through really quite a nice shot...but the sourness is still a little strong. Conclusion here is that its partly the beans, but...

I also bought some of the beans that I always used to buy pre-ground for my old machine. I also had a double espresso in the shop made with the same batch of beans so I have a pretty good benchmark on these.

Using these beans this morning to pull a double shot (17g in 26g out), the results are pretty close to what I had in the shop - but there is still a slightly stronger sour note. While there is still the possibility of a variation in technique/weights/tamp/time, I still think that temperature is partly to blame...I have the new thermostat - i'll try to get that fitted over the weekend if I have time & see if that helps as well.


----------



## Chris_on_caffeine (Jul 21, 2012)

Just seen this. The Kenya & Sumatra are pretty powerfully acidic coffees. The BUF Remera is also acidic but much more gentle.


----------



## Charliej (Feb 25, 2012)

smokeybarn said:


> Just seen this. The Kenya & Sumatra are pretty powerfully acidic coffees. The BUF Remera is also acidic but much more gentle.


The Sumatran wasn't coming across as massively acidic at all to me when brewed in a V60 02 drip decanter, but I was hitting the tasting notes bang on with an incredible smell of a wonderfully boozy tiramisu with the fruity notes of a good sweet marsala.


----------



## Chris_on_caffeine (Jul 21, 2012)

Charliej said:


> The Sumatran wasn't coming across as massively acidic at all to me when brewed in a V60 02 drip decanter, but I was hitting the tasting notes bang on with an incredible smell of a wonderfully boozy tiramisu with the fruity notes of a good sweet marsala.


Cool, glad to hear it! I thought he was talking about espresso though?


----------

