Wednesday, 28 September 2011

Espresso Brewing Control

I'm throwing this up here quickly as I'm in a bit of a rush to catch a flight to London for the Lunch! trade show, so apologies if it's not well thought out... but then, when is it ever? :)
I've decided it is time to start using the TDS meter on espresso, to hopefully gain better a better understanding and more control over my extractions using more than purely my senses. My first few measurements have caused confusion. Afraid I can't apologise for the geeky number-crunching - that's what this is all about. Maybe some readers will be interested though.

Andy Schecter produced the following brewing control chart a few years back. If you're familiar with the SCAA/SCAE brewing control charts for non-espresso coffee then this chart should be clear enough.

 So I made two shots just to dip my toe in the water and see where I ended up on the chart.

Shot 1 came in at around 5.2% TDS, shot 2 around 6.5%. Both 18g dry weight.
I let shot 1 run longer, so the beverage weight was 36g (a normale, at 50% brewing ratio). Shot 2 was a shorter 25g (ristretto at 73% brewing ratio).

1. My TDS readings are at the low end of Schecter's scale. I'm struggling a little to see how to achieve something like 20% TDS, to be honest, and wondering if my TDS meter is more inaccurate than I realised. I'll run more shots over the coming days to see what my max/min TDS range is with the beans I have and a few constants.
2. My extraction yields are also on the low side, at around 10.5% and 9% respectively for the two shots. If I raise the TDS, of course, the yield will also increase. Or if the beverage weight were greater (i.e. lower brewing ratio) that would also deliver a higher extraction yield, in theory. But that suggests that to produce a shot that would appear on this chart it would have to be a Lungo, and that can't be right. It must be possible to produce a ristretto that has a sufficiently high TDS and extraction % to marry up with the numbers Schecter used to produce this chart.

Of course, the chart could be bollocks, but Schecter has never let me down yet so I'll discount that option.

I'll keep experimenting.  My aim isn't to produce something that would tick Schecter's boxes though - I just need to understand why my figures are so low.

**EDIT** I've been informed that my TDS meter, which uses conductivity to calculate TDS, is indeed likely to be unable to give an accurate reading in espresso. If only coffee refractometers were not so expensive.  Time to shop around.

Friday, 16 September 2011

Kalita Kantan video

I knocked this up for a thread on
I still need to grind finer, but it's almost where I want it.

Wednesday, 14 September 2011

Kalita Kantan again

Tried again today with a bag of Monsoon Malabar that was roasted a week ago and is still seriously gassy. Stupidly I decided to go with the Kalita Kantan dripper... stupidly because with such a small filter basket there isn't really much room for error, and then when the bloom steals all of your remaining space it becomes quite difficult to pour water in!

Attempt One.
I used 15g of grinds and 225g of water for a 15:1 brewing ratio.


(a) I should have used a smaller dose, perhaps 10g, and increased the brewing ratio to something like 18:1, for approx 180ml in the cup. That would have given me more basket space for expansion.

(b) I should have ground coarser. I used 19 on the MDF grinder, same as I use for the Hario V60.  I seem to recall now that I had the same problem the first time I used a kantan, but I'd forgotten.  Contact time ended up being about 4mins 30secs.  Next time I'll try setting 24.

(c) Stats:
TDS 1.61%
Extraction Yield 24.2%
It sure tasted strong, but not overpowering.  I tried a few mouthfuls and then, horror of horrors, decided to finish it with a spoonful of sugar. After all, I didn't brew it correctly so I can't expect it to be sweet enough.

Attempt two.
I've worked out that with 10g and 180g water, I have a fairly small window to hit if I want to brew within the ideal standards.  With such a low dosage the extraction % ramps up easily, and to achieve an extraction % of, say, 20.7% I'll need to keep the TDS at the very bottom of the ideal range, 1.15%.  This is going to be a challenge. Maybe I'll set the grinder to something like 28 instead! 

OK - done. 10g with 200g if water. 20:1 ratio.  Results...
TDS 0.61% !
Extraction 12.8% !
Extraction time about 1min 20secs.
Taste - like water, as you'd expect with those stats.
OK, the grinder setting was clearly way to coarse.
BUT the pour was much easier to control with 10g in the basket. Just the right amount of room.

Attempt three
10g with 180g water.
Grinder setting 23
TDS 0.84%
Extraction 15.1%
Extraction time 1min 30secs
Closer but nowhere near a cigar yet. Still like water. 
I've boobed in making the grind so much coarser.  I forgot that by reducing the dosage from 15g to 10g there will already be a quicker extraction and lower TDS.

Attempt four (sigh!)
10g with 180g water.
Grind setting back to 19, same as Hario V60
TDS 1.02%

Extraction 18.4%
Extraction time 2mins 10secs. 
Performed quite a bit of stirring with a chopstick, since it was drawing down too quickly and I wanted to get the TDS up.
Taste: Now we're getting there. 67C in the cup, which is a temperature I'm happy with, and I then like to let it cool a little, to about 63C, before drinking because I find that's when I can start to taste the coffee better rather than wincing at the heat. It's less bitter at 63C too.
Actually, this is a good cup of coffee.  I didn't think I'd be saying that about this bag of Monsoon Malabar, because it's certainly very different from the other coffees I've been drinking. I know the stats are outside the ideal zone, and next time I'll grind on setting 17, but I'd be happy to drink this cup and maybe MM doesn't need such a high TDS because of it's intensely rich, deep flavours.  Just a thought.


Tuesday, 13 September 2011

Pourover 3: Grind, Pour and Agitation

Getting there.  I'm managing to brew into the "Ideal" zone of the Brewing Control Chart more frequently now.  Key findings include:

1. Grinding coarser than before.  Since I'm now making several pours instead of one or two (to maintain a higher average temperature in the slurry), the grinds aren't rising as high in the filter and aren't sticking to the sides.  This means that there is more water resistance because the depth of the grinds in the base of the filter is thicker.  This slows down the extraction. To compensate I've had to grind several notches coarser.

2. As mentioned above, temperature is staying higher. By the time it reaches the cup it has dropped from boiling (the water, just before filling the pouring kettle) to an average of 60C.  I believe most of the temperature is lost through the V60 cone, which is the transparent plastic one.  Anyway, I need to find ways to maintain a higher temperature for longer, since the resulting coffees are heading towards sourville.  (My French Press coffees are averaging 65C in the cup and are free from the sourness.)  A metal filter cone perhaps? Also maybe a better pourover kettle, since this one is cheap & thin and therefore may lose heat.

3. The pour itself is much more skill-based than I had thought.  It's not purely the aim, nor the speed, nor technique, nor adhering to a video tutorial that someone else has recommended.  The skill comes from reading the bean, and adjusting the pour accordingly to ensure the correct extraction.  How much is it blooming? What were the TDS/Extraction Yields in earlier pours using the same beans, so that you can now pour higher/lower readings without using a meter (i.e. in a busy shop environment).  Simply pouring the same way every time is definitely NOT the way to consistency in the cup.  The beans are changing, so the pour must compensate.  The barista must 'dial in' his pour to the beans each morning, and throughout the day.  Thinking about it now, changes to the grind might be a better way to compensate, in the same way as an espresso grind must be constantly re-dialed.  More experiments necessary there.

Anyway, here's a recent video showing two different V60 pouring methods and results...

Monday, 12 September 2011

Wine Aroma Wheel

Created by UC Davis, this may prove useful in conjunction with the Ted Lingle's Coffee Flavour Wheel.

Friday, 9 September 2011

Pourover 2: Beans too fresh?

For a while now I've been wrestling with the concept of degassing and its impact upon brewed coffee (rather than espresso). Opinions are mixed concerning whether in general you should or shouldn't still give them a few days to degas, or just use them asap ... just allowing maybe a day or two post-roast to develop.

Today I've been continuing an experiment I'm conducting over the coming weeks, using a large selection of beans from different regions and with different characteristics, and seeing if there is an optimal brew method to use. It follows on from this thread on

Anyway, I'm adhering to the Brewing Control Chart, and discarding any coffees I make that don't meet an acceptable range for TDS and Extraction %. It's a new approach for me, but I'm loving the insight it's providing. Today (the 9th) I opened a bag of Monsoon Malabar that was roasted by Has Bean on the 6th. I brewed 16.5g in 265g of water (16:1 ratio), through a French Press and also a Hario V60. The bloom on both was HUGE... beautiful to watch!

I gently dunked the crust on the Press.
I carefully swirled the slurry in the pourover to get a dome-shape at the end of the drawdown.

I then poured them both into cups and took measurements with my TDS meter.

French Press:
TDS 1.61%
Extraction 25.9%

TDS 1.81%
Extraction 29.1%

Significantly outside my target... right at the top right corner of the chart (off the chart, actually). The colour was very dark, and both tasted like treacle, which despite Monsoon Malabar's unique flavour characteristics, was not acceptable.

But WHY were the readings so high? I'm quite sure the grind was ok. The water temperature certainly wasn't too high. The contact time... 4 mins 30 seconds for the French Press, around 2 mins 50 seconds for the pourover... both are usually fine. Turbulence? Aaah...!

I could be wrong, but I think the degassing/blooming was so violent that on it's own it would have provided more than sufficient turbulence. By further agitating the slurry, even though it was only very mildly, the extraction has been pushed too far.

I'll try two things: 1. Give the beans another day to outgas before using them. 2. Avoid and manual agitation of the slurry for a few days.

If I'm right, then this potentially highlights how critical it is for baristas to use all means at their disposal to evaluate the current state of the beans and adjust their brewing technique appropriately. The TDS meter is only the start for me, as I'm aware that it is knows to have accuracy problems. An ExtractMojo is expensive, but not in comparison with the cost of good beans, which would be wasted if the barista is unable to get the best from them because they are just guessing how they will respond to extraction.

Thursday, 8 September 2011

Pourover: I've been doing it wrong...

After finally having a proper read of Scott Rao's 'Everything but espresso' book I've changed a few things and had another revelation.

I had been aiming for a cone shape in the spent grinds of my Hario V60 pourover filter, after watching a multitude of youtubes/vimeos and also attending a local coffee club.

But Rao explains how that's all wrong, and doesn't evenly extract. Amongst other factors, I need to be aiming for a slight doming, and avoid grinds being left "high and dry".
Here's today's filter.

This demanded a complete change to the grind, the pour, and also a more careful attitude to water temperature.

I've combined this with starting to measure TDS and Extraction Yield, to try and fit into the SCAA/SCAE Brewing Control Chart's 'ideal' range.

Result: the same amount of time, slightly more effort, and a hugely delicious cup of Sidamo which I'd previously been unable to describe as anything more than 'hmmm... tolerable'. It is now a very stable cup with clearly distinguishable features of boldness and also bright, sweet fruitiness.

I love finding out I've been doing it wrong. True progress.

Wednesday, 7 September 2011

Home-Roasted Coffee - My First Attempt

There have been some interesting discussions regarding roasting on recently.  Plenty of us are not roasting yet, but we are definitely roast-curious.

So I thought I'd give it a bash.  I have:
- beans (natural processed arabica... possibly typica) from near Munduk, Bali
- a pan
- a colander
- a hob

Here goes.

The beans have had 5 days since roasting to degas and develop in a sealable coffee bag, and today I made some coffee. French Press. The bloom was actually huge... I was very surprised.  So I was careful not to agitate the slurry too much.  Actually I should have, because the TDS came out at 0.99%, so the extraction yield was only 15.9%. But it still tasted strong, so who knows!

The body and mouthfeel are actually quite light considering the beans were dry-processed.  Perhaps something to do with my relatively light roast.  No tackiness in the mouth, but there is a mild lingering aftertaste.  There's no bitterness, but the coffee isn't sweet either.  I think it's the first coffee I've tasted that is salty! Can that be good? I suspect not :) But it's not one for the spittoon just yet.  Not much acidity at all, if any.
Actually, as it cools it's improving a little... or maybe it's just that I'm getting used to it. 

Rubber... I think maybe I scorched a few in the pan.
Yeah, the Grassy taste is coming through now.

Whilst it's clearly not a top notch cup of coffee, I think that considering it has come from an unknown farm and been subjected to a terrible roasting process, it's actually ok.  It might perhaps make a decent espresso base, come to think of it. Well... maybe not this batch, but perhaps a future one, once I get the hang of it.  But a little milk might go very well, I think... and I don't even like cappuccinos.

Friday, 2 September 2011

Tamping. How hard is 30lb?

I thought I'd throw together a short video to show what 30lb of tamping force looks like.  The Espro tamper has an inbuilt mechanism that is calibrated to 30lb so you know when to stop pressing down.

I was tamping much harder before I got this tamper.  It has been a really useful little tool, and has helped prevent spritzing when using the bottomless portafilter.