Gismar Senior Member Joined: 20 Jul 2010 Posts: 6 Location: Norway Expertise: I live coffee
Posted Mon Oct 4, 2010, 8:35am Subject: Drying phase, and internal development (Diedrich Hr-1).
If someone here has pictures of the inside of the bean, at different stages that would be great. Or maybe somone could post a link to a page that shows the different stages of internal development. I am having quite a struggle with a Guatemala SHB bean (Guatemala Antigua Los Volcanos), that I suspect I am underdrying, but there is such a fine line between underdeveloped and overdrying in this case. For some reason I get either burned or green taste in finished roast. I get 1st crack at 190 C/375 F, slow it down and spend 4 minutes til finish at 206 C/403 F I have not experienced a bean that has given me such problems.
I used a sharp knife and checked the drying development in different stages in the roast. I am very interested in seeing av SHB beans internal development at approx. 150 C/300 F. When I check the internal development at 300F, the bean is not 100% dried, should it be 100% finished at 300F? Or can the drying end as late as 320 F/160 C? Im roasting on a Diedrich Hr-1 roaster. At this roast My start temp is 340 F/170 C, and spend approx. 7,5 minutes to 300F.
If other Diedrich Hr-1 owners would say something conserning drying times on soft/medium/hard beans, I would be very grateful:-)
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,018 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Mon Oct 4, 2010, 12:04pm Subject: Re: Drying phase and internal development on Diedrich Hr-1.
Welcome to CG!
The Willem Boot article "Ruling the Roast II" may have some of the answers you look for but all are great.
I keep thinking you may hung up on the drying phase since all three phases work together to accomplish the results you are roasting for. 7.5 minutes to end of drying phase is an awful long time. What did you do after drying phase to first crack? How long was the overall roast? Are you roasting a full pound of beans?
You can compare the color of the bean after grinding to the color of the outside of the bean. If the grind is a lot lighter then the outside of the bean then not enough heat got to the center of the bean, this is important with pre second crack roasts especially although a dark roast with a lighter center can give a spectrum of flavors that can be pleasing.
Gismar Senior Member Joined: 20 Jul 2010 Posts: 6 Location: Norway Expertise: I live coffee
Posted Mon Oct 4, 2010, 1:07pm Subject: Re: Drying phase and internal development on Diedrich Hr-1.
germantownrob Said:
I keep thinking you may hung up on the drying phase since all three phases work together to accomplish the results you are roasting for. &.5 minutes to end of drying phase is an awful long time. What did you do after drying phase to first crack? How long was the overall roast? Are you roasting a full pound of beans?
This is a full batch, 1 lbs. The overall roast was approx 15,30, the final ramp was 4 minutes, that will give approx 4 minutes from 300F to 1st crack. I will check my profile later and be more specific. I try to speed up the ramp between 300F and 1st, but it is difficult to get the roast moving forward, thats why I suspect that the beans havent been dried enough. I also experience the same problem when lower batch to 400 grams. I open for 50% airflow when yellow. I open for full airflow at approx 350 F and reduce heat just prior to 1st. This gives 4 minutes to 403 F. If this ramp is longer om faster I get very burned taste in the cup.
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,018 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Mon Oct 4, 2010, 2:54pm Subject: Re: Drying phase and internal development on Diedrich Hr-1.
Gismar Said:
This is a full batch, 1 lbs. The overall roast was approx 15,30, the final ramp was 4 minutes, that will give approx 4 minutes from 300F to 1st crack. I will check my profile later and be more specific. I try to speed up the ramp between 300F and 1st, but it is difficult to get the roast moving forward, thats why I suspect that the beans havent been dried enough. I also experience the same problem when lower batch to 400 grams. I open for 50% airflow when yellow. I open for full airflow at approx 350 F and reduce heat just prior to 1st. This gives 4 minutes to 403 F. If this ramp is longer om faster I get very burned taste in the cup.
So your overall time looks fine, I was thinking it was going to be much longer since you are spending 7.5 minutes to get to the end of drying (yellowing). Your temps are different then mine, I finish drying at 300f-320f and first crack is at 400f finishing around 427f but that is a matter of probe placement that could cause these differences. It is bean mass temp you are referring to correct? You are spending more time drying then in any other phase of the roast, I would say you are over drying and not under drying. Since this is a hard bean I am seeing no reason for a 7.5 minute drying phase, I would personally cut that back to 4-5 minutes and spend more time getting to 1st crack with lower heat so the bean roasts more evenly on the inside, just my opinion, but it sounds like you have tried this as well.
Chang94598 Senior Member Joined: 24 Oct 2007 Posts: 208 Location: SF Bay Area
Posted Mon Oct 4, 2010, 5:00pm Subject: Re: Drying phase and internal development on Diedrich Hr-1.
Try CLOSE the vent when drying finishes, around 150-160C. The majority of chaff should have been blown off by now. At the same time, increase heat until just before expected first crack temperature, and reduce heat about 2 degrees C before expected first crack temperature. When first crack starts, open the vent slightly to evacuate the smoke; excessive smoke particles increase bitterness. Turn off the heat about 30 seconds before dumping the beans. The energy in the drum and heating element should provide enough residual heat. I don't know the details of the Diedrich, but the cooling bin/stirrer/fan should be also turned on about 10-30 seconds before dumping the beans for efficient cooling.
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,018 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Mon Oct 4, 2010, 7:57pm Subject: Re: Drying phase and internal development on Diedrich Hr-1.
Chang94598 Said:
Try CLOSE the vent when drying finishes, around 150-160C. The majority of chaff should have been blown off by now. At the same time, increase heat until just before expected first crack temperature, and reduce heat about 2 degrees C before expected first crack temperature. When first crack starts, open the vent slightly to evacuate the smoke; excessive smoke particles increase bitterness. Turn off the heat about 30 seconds before dumping the beans. The energy in the drum and heating element should provide enough residual heat. I don't know the details of the Diedrich, but the cooling bin/stirrer/fan should be also turned on about 10-30 seconds before dumping the beans for efficient cooling.
I think it should be the same set as my ir-1...fan 50% draw, 100%draw...or none.... and no stirring arms, and 50% is split between tray and drum or 100% cooling tray and of coarse off. I have 1 motor for both cooling and drum vent, not sure if HR-1 is different.
Edit: Henry you have a far better understanding of the chemistry of the roasting then I do any thoughts on this bean in particular?
Gismar Senior Member Joined: 20 Jul 2010 Posts: 6 Location: Norway Expertise: I live coffee
Posted Mon Oct 4, 2010, 11:55pm Subject: Re: Drying phase and internal development on Diedrich Hr-1.
There are no tipping or scorching.
The Hr-1 is similar to the Ir-1, except that Hr-1 is electric. It has 3 heat levels, low, medium and High. Because of the electric heat it has quite a delay when doing adjustments. To get it to slow down when 1st crack starts, I have to do the adjustment a minute or two earlier. Thats why airflow is an imortant temperatur control on the Hr-1. Maybe I should use 400F as charge temperatur, and slow it a bit down after drying has finished and see how it affects the cup. It is allways a choise between charge temperatur and wich heatlevel to choose when starting the roast. If I charge at 400F and has the heat setting on "High", it will go much to fast up to 300F.
If somebody could say a few things about "charge-temp", "heat level"(Low medium high) on a drum roaster like the Diedrich, I would be grateful. Would be correct to say this: SHB beans like Guatemala and Kenya can be dried at shorter times but at a higher heat level meaning charge temp and heat setting? Medium hard bean like a Brazilian will dry in a longer time but at lower heat level(lower heat setting and lower charge temperature)? I have been using airflow like this: 50% when yellow, and Full airflow just prior to 1st crack on the light roast, and full airflow at approx 400F when I roast for espresso.
Symbols: = New Posts since your last visit = No New Posts since last visit = Newest post
Forum Rules: No profanity, illegal acts or personal attacks will be tolerated in these discussion boards. No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum. No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum. Who Can Read The Forum? Anyone can read posts in these discussion boards. Who Can Post New Topics? Any registered CoffeeGeek member can post new topics. Who Can Post Replies? Any registered CoffeeGeek member can post replies. Can Photos be posted? Anyone can post photos in their new topics or replies. Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts. Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
= No New Posts since last visit 