Turbofan or Unox which one is better for cocoa bean roasting?
@kinsol - It has been over a year since I looked closely at Unox ovens and to be quite frank the only meaningful difference I can see is the size of the sheetpans. The Cheftop appears to be US-sized pans (18x26 inches) and the Bakertop are EU-sized pans (600x400mm).
@DiscoverChoc Are we talking about the CHEFTOP or BAKERTOP from UNOX Mind.Maps series?
@Wendy0419 - In my experience, the five-pan Moffat is less expensive than the smallest full-size sheet pan Unox ovens. Programmability is helpful when it comes to repeatability and consistency - you can program the oven for a specific length of time at a specific temp and can then raise or lower the temp programmatically. In some combi ovens you can program the humidity, too. (I try to recommend these.)
From a UCDavis document on controlling salmonella:
Microbiologists have identified at least 11 factors or parameters of microorganisms and their
environment that can affect heat destruction. These factors include moisture or water activity, fat levels, presence of salts, presence of carbohydrates, pH, protein content, number of organisms, age of organisms, inhibitory compounds, and time and temperature history. Despite the influence these factors can have on the resistance of microorganisms to heat, thermal destruction during the processing steps [...] is the most critical control step for destruction or
reduction of Salmonella and other pathogenic microorganisms.
From the article:
Generally, Salmonella becomes more heat resistant as the water activity of a food becomes lower [...]. For example, it takes less than 5 minutes to achieve a 5-log reduction of Salmonella at 140 °F in a food with a water activity of 0.99 [...]. However, it takes 50 minutes to achieve the same reduction of Salmonella at 140 °F in a food with a water activity of 0.85 [...].
Thank you @DiscoverChoc I wondered would you willing to tell me more about the defect of the programmability? Price wise the Unox is a lot cheaper than Turbofans. In addition, I might need some suggestions about the time and temp about using steam for a microbial kill process.
@Wendy0419 - There are advantages to the programmability of oven like the Unox, they mean greater consistency in roasting. However, that programmability comes at a cost. The Moffat turbofans are good ovens used properly.
Whichever oven you decide on, make sure that you get one with steam and that you plumb it in. Steam at the start of a roast cycle will improve the microbial kill, reducing salmonella and e coli (if present) on the outside of the beans.