Drying Phase During Roasting

[paypalboutique]

When starting a roast, the green beans go through their phases. Once the green bean turns and the temperature goes up, what are your experiences with the drying phase? Like what temperatures do you turn the fan on to remove moisture and what happens to the taste of the bean if you don't remove the moisture during roasting?

 

[ensoluna]

hi paypalboutique. i am not 100% sure exactly what you are asking, but let me illustrate how we roast our beans.
we have 30lb roasting machine. we pre-heat to 400F and put green beans (about 25lbs). we do not want to put no more than 25lbs at one time because beans get scorched against the drum if there are too much beans. as soon as you put the beans, the temp drops to 220F. and slowly goes up as the beans get roasted.
as beans get roasted, THE BEANS LOSE MOISTURE and expand. depends on the roast (medium, med-dark or dark), we adjust time and temp. about 16 min into roasting, and the beans are ready, all the roasted beans get dumped into a vented tray with rotating stirrers. hot air from beans get sucked into the vent as beans cool. we need to cool the beans immediately from keep roasting.

this is our simple roasting explanation.

"Like what temperatures do you turn the fan on to remove moisture and what happens to the taste of the bean if you don't remove the moisture during roasting?" - either you are talking about something else, I do not quite understand what you are asking.

anyway, if you have any more question about bean roasting matters, please let me know. I will try to explain to you as much as I know.
thanks

 

[paypalboutique]

I was roasting using a hottop roaster and an Indian robusta with a roasting profile, it came out tasting the way it should with light spice taste and some earthiness. Ambient temp was 74°F and 62%RH. I used 275g green beans. I heated the roaster to 431°F and dropped the beans in. (All temperatures are machine display of internal temp) Temperature dropped to 240°F and when it got to 300°F, fan was turned on 75% for 30 seconds to draw out moisture so chaff dust doesn't collect on viewing window glass. After that, fan remained off to bring temperature up faster until 350°F then turned fan on to 25%. At 370°F fan was turned to 75%, beans turned cinnamon color, and first crack began around 384°F at 7:50 min. First crack ended and roast was pulled at 9:00 min. with a city roast finish temp of 417°F and a 15% weight loss. I removed a sample and heated up roaster and continued roast until full city, pulled it, reserved another sample, and continued roast again until vienna. All tasted the was it was supposed to.

Seven days later, I performed 8 consecutive roasts with the same bean from the same 132lb burlap bag. Each roast was 275g weight with starting temp from 230-253°F. I used the same roasting profile as the previous roast and had similar results. Only variations were turning temp was from 375-380°F, ambient temps 69-74°F, 44-51% RH. That day only a few beans hit first crack and it happened around 9:30 min. Pulled around 11:30 min., finish temp 410-415°F. Visually appeared to be city roast with 13-14% loss. Tasted grassy, not very good. Distributor notes that this bean tastes grassy when first harvested and grassy taste goes away with age and taste improves. Its a July 2013 harvest purchased in July 2014 and came in a double burlap bag no plastic. Bean moisture shouldn't be a problem. Its a problem I have sometimes with robusta, it not hitting first crack sometimes, even with similar ambient temps and RH. Is not hitting first crack making the difference or too much moisture during roast? I tried re-roasting similar to my batch 7 days prior, but didn't help the taste.

 

[ensoluna]

yes, now i understand what you were saying. but sorry that i have never used hottop roaster before, so I do not know.
hopefully some other forum members are be able to help you on the subject. thanks for clearing that out for me.