# Slow draining brews



## Step21 (Oct 2, 2014)

I'm pretty sure most of us have brewed up an Ethiopian Yirgacheffe and waited an age for it to drain in a variety of brewers. It can cause chaos with recipes based around drawdown time.

I have been dabbling in the black arts of roasting and have a theory about how this happens. But before expanding on this I'd like to get you to post up the "culprits" to see if there is a pattern.

In particular, I'd like to know if you find these beans

(a) light in colour - light brown or paler (indicative of a light roast)

(b) Are they unusually hard to grind at your usual setting?

© for anyone with a Kruve sieving set if they would be kind enough to check if the distribution of grind sizes is unusual?

So to kick off :-

1. Ethiopian Yirg Rocko Mountain, home roasted, heirloom varietals, natural process, very pale brown, hard crunchy grind for normal immersion and drip. Extended normal drain time (Bonavita Immerssion brewer) by around 1 minute.

2. Columbian La Quebradilla, home roasted, F6 & castillo varietals, washed process, light chocolate brown, hard crunchy grind. Extended Bonavita drawdown time by nearly 2 minutes, very noticeable slowdown on the last quarter of the drain.

I didn't take TDS readings of these but will in future. They both tasted good to great over 3 brews each. So the extended drawdown didn't cause me any taste problems.

I have roasted these beans in 3 different ways and only when I choose a particular type of profile do they exhibit this phenomenon. I plan to do this with more different beans to get a larger sample size.


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## Batian (Oct 23, 2017)

Is there a difference between the altitudes that the two beans are grown at?

High altitude often makes for a harder bean compared to those grown at a lower altitude. It also affects the flavour density.

It's all connected to the length of time taken for the cherry to mature on the plant.

If you are using a Gene Cafe, are you following the instructions re charge weight differences for natural and pea berry vs wet processed? That could introduce a whole load of new variables!

You touched on grind, are you able to makes sure that the size of the coffee grains is the same for both types, as I am sure that is going to affect the rate of flow?

Interesting project, I look forward to seeing your results.


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## Step21 (Oct 2, 2014)

The Ethiopian is 300m higher grown than the Columbian. I don't use a Gene Cafe. I'm using the Ikawa Home roaster.

As to grind size, I'm simply grinding at my usual setting. I don't have any way of establishing comparitive grind size ratios of different coffees at the same setting.

It is a while since I had a commercial roast that exhibited this. The last one i remember was an Ethiopian natural Yirg from Craft House coffee last year. It was a light roast and a hard grind.

Previously, I thought that this was a feature of the bean. But if I can induce this on a lot of different coffees then it is more likely a roasting phenomenon.

In a sense it doesn't really matter how but if it is the roasters choice then some warning might be appropriate? If.


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## MWJB (Feb 28, 2012)

Whilst this is perhaps most noticeable with Ethiopians, it can affect other African coffees too, occasionally Brazils.

Maybe the lighter roasted examples are more brittle (hence hard to grind), they sometimes appear to grind finer but I haven't measured anything in that department.

FWIW...

50 brews with a Brewista Smart steep, same grind setting for all, 90s bloom, open valve, dump water straight in, stir surface. Av. brew time 4:51, StDev 113sec.

4 longest brews were Burundi Kibingo 6:50, Malawi Msese 7:00, unknown Ethiopian 12:31, Wenago Gideo Yirg 13:00. The ~7:00 brews were still very tasty, the absurdly long brews were not. This brew method with some Ethiopians has caused me to abandon a couple of brews with a natural Ethiopian, as it was never going to drain. A natural Brazil was 5th slowest, but within the bounds of normal.

See here for my last slew of 10 brews, same grind & pour regim with Kalita Wave...

https://docs.google.com/spreadsheets/d/18d9L9J_4YeHHiz8257JZ-2-W-CJaaAqYRCP-YOs4650/edit?usp=sharing

I think a lot of the time these situations can go under the radar with roasters if they don't grind by hand, or if they evaluate production roasts by immersions (cupping).


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## garydyke1 (Mar 9, 2011)

Kenyan coffee is worse for this !


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## the_partisan (Feb 29, 2016)

I usually just stop my Kalita brews if it'll take more than 5 minutes, you'll lose some liquid but not a lot.. Very gentle pouring and/or using something like Aeropress cap seems to mostly avoid this problem, but it seems likely related to bean density and how many micro fines (0-50um? filter pores are 20um) are produced by the grinder.


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## the_partisan (Feb 29, 2016)

MWJB said:


> See here for my last slew of 10 brews, same grind & pour regim with Kalita Wave...
> 
> https://docs.google.com/spreadsheets/d/18d9L9J_4YeHHiz8257JZ-2-W-CJaaAqYRCP-YOs4650/edit?usp=sharing


Kind of off topic but I use these formulas for EY and LRR, assuming 3% moisture and 1% CO2 in the bean:

EY (drip) = (BEVERAGE*TDS)/(DOSE*0.96)

LRR (drip) = (BREW WATER - BEVERAGE - DOSE*0.03 - BEVERAGE*TDS)/(DOSE*0.96)

LRR is more tricky than it looks because the beverage weight includes the H2O content and the dissolved solids from the bean. Would like to code an app that makes entering this info convenient, but haven't had time for it yet..


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## MWJB (Feb 28, 2012)

the_partisan said:


> Kind of off topic but I use these formulas for EY and LRR, assuming 3% moisture and 1% CO2 in the bean:
> 
> EY (drip) = (BEVERAGE*TDS)/(DOSE*0.96)
> 
> ...


I just put the measured weights on my sheets, then enter 'gm bev' into the software & let it generate it's LRR


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## Step21 (Oct 2, 2014)

MWJB said:


> Whilst this is perhaps most noticeable with Ethiopians, it can affect other African coffees too, occasionally Brazils.
> 
> Maybe the lighter roasted examples are more brittle (hence hard to grind), they sometimes appear to grind finer but I haven't measured anything in that department.
> 
> ...


Wow! That's surprising to me and seems much more widespread across varietals and altitudes than I would have thought. Can you correlate any of them to a tough grind? The Brazilian natural doesn't surprise me as I've seen some really light roasts with them. I'm pretty sure I've had some crunchy grinds with them before but no actual recording of it. Those Ethiopians are ridiculous! How could a roaster not pick that up? It very well might stop you ordering from them again.

I think it is the brittleness that causes the issue and my initial theory is that this is caused mainly by how the beans are treated in the drying stage of the roasting process by the roaster.


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## the_partisan (Feb 29, 2016)

MWJB said:


> I just put the measured weights on my sheets, then enter 'gm bev' into the software & let it generate it's LRR


Sure, but it's more convenient for me not to have the open the software and just directly put things into a sheet







Esp. since I typically can vary my doses and don't discard extra grams.


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## MWJB (Feb 28, 2012)

Step21 said:


> Can you correlate any of them to a tough grind?.


The Ethiopian natural that completely stalled the brewer gave me a sinking feeling whilst grinding, it was like grinding stones.

Maybe I'll start recording how tough a grind beans are. But really, I expect lighter roasts to be tough, especially if the coffee is still pretty soluble, or a natural & it's still fairly rare that a coffee will actually be problematic in terms of actual extraction - the Brewista brews were probably more susceptible & highlighted the issue because of a relatively fine grind & an unsually wide, flat bed.

As @the_partisan says, a dispersion screen, rather than pouring with a kettle, can help (see the lower variation in brew times with 'Kalita Wave/OXO' brews).


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## Step21 (Oct 2, 2014)

Sure a dispersion screen helps, I do this on all my brews. A non plunge French Press might be another way of dealing with these types of beans.

But a light roast doesn't have to have to be hard to grind. This is one way of doing it. I guess a lot of roasters like it and so far when I've tried it the results have been good.

I tried another Columbian that I roasted in this way this morning and sure enough it was a hard crunchy grind but interestingly it drained in a normal time. I don't have details of the cultivar or height grown for this one. Very tasty though.


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