Sour shots from heatgun roast

Roasters and roasting

Moderators: GreenBean, Gouezeri, bruceb, CakeBoy

Sour shots from heatgun roast

Postby Bombcup » Tue Dec 11, 2007 10:50 pm

I've not been having much joy from my espresso just lately. I've tried roasting Brazil Fazenda Cachoeira Bourban, Guatemalan El Injerto and most recently Costa Rican CoE Libano Coop, all chosen because of their lack of inherent acidity.

Unfortunately all of these have left me with an expression like a dog's arse. The only coffee I have found palatable with my own roasting has been a Mysore with an incredibly powerful musky taste.

If I may bore you for a minute here is my roasting routine:

250g greens in a sieve inside a well fitting hevy saucepan, heatgun pre-warmed, tunes on, aromatic ciggie lit.

Hold gun 25mm above centre of bean mass and stir vigorously.

First crack fully under way at 11 mins.

First crack drawing to an end at 14 mins.

Withdraw heatgun to around 150 - 200mm until 17 mins to slow down temp ramp up.

Move heatgun back to 25mm above beans to induce second crack around 18 to 19 mins.

Stop roast after first few pops of second crack and cool quickly between two sieves.

Leave in open bag overnight, seal bag the following morning, leave 24hrs.

I hope somebody may be able to troubleshoot this routine and see where I'm bringing the acidity into the roast. Roasted coffee costs more per week than smoking and I really enjoy the roasting so any help would be much appreciated.

Many thanks.
User avatar
Bombcup
 
Posts: 860
Joined: Thu Sep 06, 2007 2:24 pm
Location: Wellingborough, Northants

RE: Sour shots from heatgun roast

Postby lukas » Tue Dec 11, 2007 11:12 pm

I presume the shots are coming out nicely off the portafilter and the temperature of the brew is ok?

I once measured the temperature of the air from my heatgun. It was around 500dgc directly in front of the exit, and falls down rapidly with every cm further away. So my guess is that the beans loose heat during the time you withdraw the heatgun (I read somewhere that the temperature of the bean should never, ever, stall while roasting, let alone fall back a bit).
Plus, the heatgun method is known for accentuating the acidy notes in coffees, whereas radiant heat roasters tend to accentuate the body.

So: try not letting the beans loose temperature after first crack (a slower temperature rise after first crack should be ok though, but it's very difficult to measure without a proper thermometer in the bean mass) and roast a bit darker than just the first pops of second.
I normally go half a minute or more into second crack (with my cast iron crank thingy though), as with my roaster that doesn't mean charcoal, but merely the same as when Steve says 'just first pops of second' as my roasts are a little uneven ...
Lukas

This week I like my coffee luke-warm.
--
Newest kit: Ghibli R-15
User avatar
lukas
 
Posts: 2798
Joined: Mon Jul 25, 2005 8:41 pm
Location: Germany

RE: Sour shots from heatgun roast

Postby Bombcup » Tue Dec 11, 2007 11:20 pm

Do you think I should just keep the gun in one position for the duration of the roast? If I keep it really close then first crack sometimes rolls straight into second giving too fast a roast. Maybe I should keep it 50-70mm above the bean mass for a slower, more even ramp-up?
User avatar
Bombcup
 
Posts: 860
Joined: Thu Sep 06, 2007 2:24 pm
Location: Wellingborough, Northants

RE: Sour shots from heatgun roast

Postby bruceb » Wed Dec 12, 2007 7:03 am

Are you sure it's your roast that is causing the problem? Have you tried fresh, commercially roasted beans?

Also, roasting as you are, 19 minutes seems awfully long. You may be baking the beans.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
Image
User avatar
bruceb
 
Posts: 5361
Joined: Sun Apr 04, 2004 12:49 pm
Location: Northern Hesse, Germany

RE: Sour shots from heatgun roast

Postby fred25 » Wed Dec 12, 2007 8:14 am

Also, have you tried drinking the roasted coffee through FP or filter or AP etc., to ensure it's the roasting that's causing the problem, not the espresso making?
Au réveil, il était midi.
User avatar
fred25
 
Posts: 649
Joined: Mon Feb 20, 2006 7:36 am
Location: sunny manchester UK

RE: Sour shots from heatgun roast

Postby espressomattic » Wed Dec 12, 2007 8:17 am

My knee jerk reaction was under roasted, however that is not apparently the case.

I doubt it is baking bruce as you get a distinct bready aroma with the shot. My roast to 2C are regulary 19 mins.

I would suggest a cooler pour in the shot. If you are reaching 2C you are getting a full roast and if anything, youwould get burnt tastes not sour.

Matt
espressomattic
 
Posts: 2950
Joined: Sat Dec 03, 2005 7:31 pm

Postby Bombcup » Wed Dec 12, 2007 9:28 pm

Thanks for the advice guys. I've been playing around with my shot preparation this evening which has left me feeling a bit wired but has been fruitful.

I think I have become a bit complacent lately as my shots were starting to become consistent, but thanks to the advice I now think I've been flushing the machine too much and cooling down the brew temperature. I also tried giving a longer pre-infusion which seems to have done the trick.

I'm still not convinced with my roasting. I've managed to dial out the sourness as described above with the Costa Rican I roasted last night but despite it now having balance it seems a little nondescript and there is still an acidic aroma which thankfully no longer transmits to the tastebuds. Maybe I'm now brewing too hot, masking the acidity but losing the more delicate flavours. No more messing with it tonight though, I won't sleep until tomorrow lunchtime!

I'll try all your roasting tips over the next few days and let you know.

Cheers :)
User avatar
Bombcup
 
Posts: 860
Joined: Thu Sep 06, 2007 2:24 pm
Location: Wellingborough, Northants

Postby lukas » Wed Dec 12, 2007 11:00 pm

Keep us updated. Could that acidic aroma be slightly sharp and smokey? It could as well be that the coffee needs a few more days of rest to come through well.
Lukas

This week I like my coffee luke-warm.
--
Newest kit: Ghibli R-15
User avatar
lukas
 
Posts: 2798
Joined: Mon Jul 25, 2005 8:41 pm
Location: Germany

Postby espressomattic » Wed Dec 12, 2007 11:03 pm

How long are you leaving for degassing?

I ask because Injerto I have found tends towads acidic if not left for a coupla three days.
espressomattic
 
Posts: 2950
Joined: Sat Dec 03, 2005 7:31 pm

Postby Bombcup » Wed Dec 12, 2007 11:48 pm

Yes it probably would benefit from a longer rest period. I roast when I get home from work and start drinking it 24 hours later. By the time I've had 2 or 3 shots in the evening, made the missus a couple of americanos, had an aeropress the next morning and a couple of shots after work it's pretty much all gone by the time it's starting to come good.

If I was a bit more organised (less lazy) I would roast two or three batches in an evening so it would get a chance to rest, but by the time I've finished the first batch the funky cigarette has kicked in and I get distracted! :roll:
User avatar
Bombcup
 
Posts: 860
Joined: Thu Sep 06, 2007 2:24 pm
Location: Wellingborough, Northants

Postby espressomattic » Thu Dec 13, 2007 12:01 am

Funky cigarette????? Tut tut tut :P
espressomattic
 
Posts: 2950
Joined: Sat Dec 03, 2005 7:31 pm

Postby CakeBoy » Thu Dec 13, 2007 12:06 am

Nice Christmas clothing Breako mate :P
www.CakeBoy.co.uk
International muffin blagger

Iberital L'Anna 1 Gp Hand-Fill | Wega Orion 2 Gp | Bezzera 1 Gp | Rancilio Audrey PID | Spidem Trevi
Iberital MC2 Timed | Macap M4 DS & MXA DS | Mazzer SJ | Starbucks Barista Grinder (Dualit E60/Solis 166)
Pinhalense 2x500g Gas Batch/Sample Roaster | Gene Cafe | IMEX CR-100
Aerobie | eSantos | Zassenhaus | Bodum P/Over | Chemex | Hario Woodneck | Timer Filter
User avatar
CakeBoy
 
Posts: 10006
Joined: Tue Oct 18, 2005 10:43 pm
Location: Oxfordshire, England

Postby espressomattic » Thu Dec 13, 2007 12:14 am

As per our convo, I find I really have to wrap up here :P

Anyway back on tpoic...

Just reading through your times Steve, I would suggest really trying to drag it out a bit before 1C say 15.5 mins and then ramping it up to 2C. You may find a longer roast profile will draw out the acidity and replace it with body?
espressomattic
 
Posts: 2950
Joined: Sat Dec 03, 2005 7:31 pm

Postby Bombcup » Thu Dec 13, 2007 12:27 am

Nice one Danish Dan, I'll try that next roast. Sadly that wont be tomorrow as I'll be off buying xmas trees, searching the loft, trying to find which bulb is stopping the lights from working, swearing, moaning, and getting further down the road to atheistic fundamentalism! Humbug!
User avatar
Bombcup
 
Posts: 860
Joined: Thu Sep 06, 2007 2:24 pm
Location: Wellingborough, Northants

Postby Bertie_Doe » Thu Dec 13, 2007 5:08 pm

I have a heatgun as backup, but I've only tested it a couple of times, so can't offer any advice. I don't know if you're forced to roast outside WC, but if not, have you tried zix's oven roast technique? He seems to get very even results and of course you can adjust the temps and do a bit of profiling.

QC
ps. Henceforth you will be known as 'outside wc' :)
Isomacs Zaffiro and SuperGiada
Hottop and Precision roasters
ECM/Pasquini K2 and Aerolatte grinders
Dental vibrator
dbl/16g/44ml
User avatar
Bertie_Doe
 
Posts: 1935
Joined: Thu Apr 28, 2005 11:23 am
Location: Cornwall

Next

Return to Roasting - Equipment and Techniques

Who is online

Users browsing this forum: No registered users and 26 guests

cron