Roasting Kenya Gethumbwini Peaberry

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Roasting Kenya Gethumbwini Peaberry

Postby voice_of_reason » Wed Jan 21, 2009 6:55 pm

I've done a few roasts now in my popper and have been pretty pleased with the results. Today I roasted a bag of Kenya Gethumbwini Peaberry (the first time I've done this bean), and it didn't go well! I think I only heard a couple of pops of first crack, but the roast was definitely progressing as the beans were getting darker and darker. I had to stop for fear of completely burning them, but I'd still only heard a couple of pops of first crack. The chaff was still coming off too, but I decided to stop and cool them down.

The result - they looked a bit uneven, with quite a lot of chaff still attached and a very mottled surface to the bean (many different shades of brown).

My previous roast (Brazil Fazenda Cachoeira) went really well, I heard first crack for quite a while, then a gap, and the first pops of second crack, so I really felt like I had things under control and they came out well. Now I've lost my confidence with this Kenyan bean! I've no idea whether they're medium or dark roasted. There's no oil visible on the surface so I guess I can't have done them that dark.

Is this bean known for being awkward to roast, or is it just my lack of experience? I'm not sure what I did wrong. I guess different beans behave in different ways.

I haven't tasted it yet (leaving it to degas for a couple of days), so maybe I should reserve judgement.
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Postby Olings » Wed Jan 21, 2009 7:32 pm

Kenyans and peaberries in particular need more heat in the first stage. The colour they have when you take a sample during roasting will lighten a fair bit when cooled down. The slow and inaudible first crack seems to me to be due to a to low heat from the start.

Brazilian beans are much more forgiving.


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Postby triptogenetica » Wed Jan 21, 2009 8:51 pm

maybe you could try oven roasting? I found it much easier than the popper (beans are laid out in a layer, not all clumped together) and chaff is far less of an issue!

With some practice, I find one can achieve a fairly even, very tasty roast. Not tried a peaberry, though.
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Postby voice_of_reason » Thu Jan 22, 2009 11:26 am

Olings - thanks for that. Using a popper I suppose there's not much I can do if the problem stems from a lack of heat at the start of the roast. To me it seemed as though they were roasting too quickly - almost as though I was applying too much heat. But then I'm quite new to this so I could be talking rubbish.

triptogenetica - I hadn't really considered oven roasting, as I always thought it would be best to roast outside. When you say chaff isn't as much of a problem, how do you mean? In the sense that it doesn't blow everywhere like it does in a popper? I suppose you then have to manually separate the beans from the chaff? I was a bit concerned as I thought a normal electric fan oven wouldn't be suitable - plus I thought it might generate too much smoke in the kitchen. I may look into it though. I'm always open to ways of improving my roasting!
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Postby triptogenetica » Thu Jan 22, 2009 12:29 pm

I chose oven roasting specifically so I could roast somewhere other than our kitchen. (I was pan roasting before - very very smoky!)

So all I did was get hold of a mini electric oven and a tray that fits it. No fan in it, so yes, the chaff doesn't blow everywhere.

I detailed my method in this thread (just scroll down a bit)-

http://www.toomuchcoffee.com/index.php? ... highlight=

I'd give it a try! I just nip down to the utility room each weekend - and roast some coffee.
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Postby voice_of_reason » Thu Jan 22, 2009 1:09 pm

Thanks very much for that - now you mention it, I do remember reading your post about the mini oven a while back but then forgot all about it. Certainly sounds interesting, and I like the idea of roasting a bit more slowly. I imagine you have to keep a very close eye on things to avoid burning and to get an even roast. Doesn't smoke become a problem in a little oven like that? Is it ventilated at all? It's nice and cheap though - I like cheap!

I may use up the rest of my Hasbean beans in the popper and try a few more origins first to see if I just experienced a temporary mishap. If I find I really can't get reasonably consistent results with the popper though, I'm definitely tempted to give the mini oven a try.

Cheers.
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Postby triptogenetica » Fri Jan 23, 2009 5:37 pm

the oven - it has vents at the sides, and like all methods there's a bit of smoke - that's why I do it in a communal utility room (where I can leave the windows open - no heating in there anyway).

I imagine the roast needs more attention than in a popper, but far less than pan-roasting!

I actually tried a popper, before the oven - i started out roasting decaf - and the thing blew a fuse almost at once. Decaf often has some broken beans in, and one of these had fallen down into the heating coils. Since then I've used the oven!
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Postby technojock » Sat Jan 24, 2009 12:08 am

I guess from your other posts you're roasting about 85g of beans. Stirring? How long before you heard FC? How long before you stopped?

Try cutting open a bean or two - is the colour constant throughout, or are they lighter inside? If they're lighter inside then they're roasting too fast and aren't "cooked through". You might find they taste unpleasant, depending on how underdone the inside of the beans are.

Unfortunately, all beans behave differently; some have clear FC/SC pops, others run them together, and others try to get through FC with hardly any sound. It might help to go by smell as well, which is how I learned to tell when SC was coming up.

Ultimately, only taste will tell. Have you tried them yet?
__

Disclosure - I never really mastered popper roasting. I found the beans roasted too quickly for me. The beans I was most successful with were those with wide roast ranges.

I progressed on to using a heatgun after I borrowed one from a friend and successfully roasted some beans in a pan one evening. If you want to try, there are quite a few sites (usually American) which discuss how hot the air needs to be, and what airflow you need.
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Postby triptogenetica » Sat Jan 24, 2009 10:43 am

I'm impressed - didn't realize I'd mentioned what batch sizes I was roasting in - and even more impressed someone remembered.

Yes, I started off with about 85-90g (the roasting tray is originally the weighing pan from a set of scales!); more recently I have found that with a bit of skill you can do about 120g at a time. I usually do 2 batches - one normal, one decaf - each weekend. It's relaxing work.

The beans themselves are beautiful after the roast; as long as you stir correctly, they're even, and well roasted through. The oven should be preheated, too.

Since I use a mini oven, preheating is quick, and stirring is really easy - you don't need to take the tray out, at all. Just reach in with a fish slice and rearrange the beans, every 3 mins or so. Stirring early is important, too.

And taste-wise - I've been drinking very nearly my own roasts exclusively since I started; it's very nice! (Had some roasted for me while in Hong Kong this Xmas though, to tide me over) :)
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Postby voice_of_reason » Sat Jan 24, 2009 5:26 pm

Was the 85g aimed at me?! If so, then yes - I am roasting 85g at a time (easiest way to split a 250g bag evenly three ways).

I split a bean or two open after roasting and they didn't look too bad inside. Fairly consistent all the way through.

I ground some for the first time this morning. It looked a little paler than the other beans I've roasted but it seemed fairly acceptable.

The verdict on the taste - not pleasant! It was literally like drinking Lemsip. None of this subtle, 'hint of' business - it was similar to sucking on a lemon. I know these beans are meant to have a citrus overtone (Steve from Hasbean says in his notes that even the uninitiated who have had their taste buds removed can't fail to notice the citrus flavours!) But this was just over the top and definitely not to my liking. I would barely have guessed it was coffee.

Now I'm not sure whether this is just down to the type of bean (I'm still very new to this), or whether what I tasted was an underroasted, green bean.

Is that what green beans taste like?! Sharp and sour?
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Postby lukas » Sat Jan 24, 2009 8:45 pm

Sounds very much like it was roasted too lightly, Mr. Reason!
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Postby technojock » Sun Jan 25, 2009 9:01 pm

Sorry guys, should have made it clear I was responding to voice_of_reason's posts. Now that I've re-read it, it does look like I'm responding to triptogenetica (who is doing a fine job promoting oven roasting).

voice_of_reason wrote:Is that what green beans taste like?! Sharp and sour?


Yes. Are you still trying to get the taste, or the memory of it, out of your mouth? Been there.:( I guess you'll be roasting the next batch soon. Try to hold your nerve and go a bit darker. When you go too far, the coffee tastes thin and weak. Been there too. :( At least it's not as shocking as the under-roasted bean.
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Postby triptogenetica » Mon Jan 26, 2009 8:29 am

When you go too far, the coffee tastes thin and weak. Been there too. At least it's not as shocking as the under-roasted bean.


And if you go really far, it'll smell like bacon. Best avoided, that one.

Don't worry, technojock - you gave me a good opportunity to hammer on about using an oven, which is always nice.
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Postby voice_of_reason » Mon Jan 26, 2009 9:22 am

technojock wrote:Are you still trying to get the taste, or the memory of it, out of your mouth? Been there.:( I guess you'll be roasting the next batch soon. Try to hold your nerve and go a bit darker. When you go too far, the coffee tastes thin and weak. Been there too. :( At least it's not as shocking as the under-roasted bean.

Yes, that's exactly it! Unpleasant to the point that I couldn't get the taste out of my mouth. Like I say, the slightly darker batch I did was much more palatable (although still under-roasted I would say).

I'll definitely hold out longer when I next roast those beans. They trick you by making you think they're on the verge of burning, but once they've cooled they look MUCH lighter. Definitely an awkward bean to deal with!

Thanks everyone for the comments. It's really helping me to learn more!
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