<P> Through season 6 the show was taped in standard definition, 4: 3 video; season 7 saw the show switch to widescreen 16: 9 video . The high definition version of the show is broadcast as part of PBS HD's master digital schedule, and by some PBS affiliates as part of their normal schedules . </P> <P> During recording, 26 recipes are videotaped during a three - week period . Six recipes are recorded per day, and there are two recipes demonstrated per episode . </P> <P> America's Test Kitchen features several recurring cast members, although not every cast member appears in each episode . Julia Collin Davison (identified on - screen before season 7 as "Julia Collin"), Bridget Lancaster, Kay Rentschler, Rebecca "Becky" Hays, Sandra Wu, Yvonne Ruperti, J. Kenji Alt (now J. Kenji Lopez - Alt), Erika Bruce, Bryan Roof and Dan Souza are the chefs who explain and prepare the recipes in each episode as Kimball watches and comments . Yvonne Ruperti and J. Kenji Lopez - Alt departed the company in 2011 and 2009 respectively . Usually only one or two of the chefs will appear in an episode . Collin - Davison, Lancaster and Rentschler appeared as regular cast members on season 1 . Since, Rentschler moved to the positions of Culinary Producer and Executive Chef by season 2 and appeared in only one episode that season, before leaving the show by Season 3 . Hays joined the permanent cast in season 5, Bruce, Wu, and Ruperti each appear for a single season (seasons 5, 6, and 8, respectively), and Alt appears in seasons 7 and 8 . All are prominent recipe testers or editors in Cook's Illustrated . Beginning in season 5, Cook's Illustrated staff chefs Hays, Bruce, Jeremy Sauer, and Matthew Card appeared in segments answering common viewer mail questions . Hays, Bruce, and Sauer joined the on - camera cast for season 6; Hays moved into credited cast member status beginning in season 7 . Roof and Souza were added to the regular cast starting season 15 . </P> <Ul> <Li> Christopher Kimball, the show's host for seasons 1 - 16, was the founder, editor and publisher of American's Test Kitchen and its associated magazine, book, television and radio programs from their inception through 2016 . Kimball and ATK parted company in the fall of 2016 over a contract dispute . </Li> <Li> Julia Collin Davison took over as co-host of "America's Test Kitchen" alongside Bridget Lancaster with the start of season 17 in January 2017 and took over Chris' role in introducing the recipes featured in each episode . Julia Collin Davison appeared in most episodes of "America's Test Kitchen" seasons 1 - 16, but will appear in all upcoming episodes (January 2017). Davison will continue cooking selected recipes on each episode with the help of current and new cast . </Li> <Li> Bridget Lancaster additionally appeared as a regular cast member in seasons 1 - 16 and joins Julia Collin Davison as host in all episodes for season 17 . Lancaster will also continue to cook through select recipes on upcoming episodes alongside other cast members . </Li> <Li> Jack Bishop appears in most episodes in the Tasting Lab segment . In the Tasting Lab, he describes a tasting panel's opinions on different brands of the food or ingredient in question, as Kimball, Lancaster or Davison tastes several of the items blind . After Kimball, Lancaster or Davison provides his or her thoughts on the different varieties, Bishop reveals the brands that Kimball, Lancaster or Davison tasted and compares his or her thoughts to those of the tasting panel . Bishop and Kimball frequently refer to a running joke that Kimball's tastes are often vastly different from the tasting panel's; as an example, in a segment tasting bottled waters, Kimball picked Boston tap water over all the brands of bottled water . Bishop also hosts the Cook's Illustrated podcast . </Li> <Li> Dan Souza is executive editor of Cook's Science at America's Test Kitchen . He's an on - screen test cook for America's Test Kitchen and a weekly contributor to America's Test Kitchen Radio . A former senior editor for Cook's Illustrated, Dan has contributed content to a dozen America's Test Kitchen cookbooks, including executing and editing the test kitchen experiments for the New York Times bestseller The Science of Good Cooking and the forthcoming Cook's Science . Dan cut his culinary teeth as an apprentice in Hungary before graduating first in his class from the Culinary Institute of America . After cooking in restaurants in New York City and Boston, however, he found his true calling: applying good science to create great recipes for the home cook . </Li> <Li> Adam Ried appears in most episodes as the host of the Equipment Corner segment . In this segment, he shows several brands of a piece of kitchen equipment and often asks Kimball, Lancaster or Davison to use several of the items or eat food prepared with different brands . In the end, he identifies the test kitchen's preferred brand and demonstrates its key features . For particularly expensive items, he often identifies a best buy: an item that was ranked highly but is significantly less expensive than the top brand . Throughout the show's run, items previously tested in other seasons have been retested as technology changes warrant; for instance, in season 8, garlic presses were retested due to the failure of the non-stick coating on the previous winning brand after heavy usage, and a new favorite brand was chosen . Occasionally the Equipment Corner segment does not focus on a single piece of equipment; instead, a "buy it / don't buy it" format is used to pick the best items among newer, trendier kitchen gadgets . One of Ried's favorite "buy it" gadgets was a timer that came with its own lanyard so cooks could wear it around their necks and not have to be in visual range of the oven timer; Ried revealed, however, that the timer was normally used to stay one step ahead of local traffic law enforcers by signaling that it was time to feed the meter or move the car . </Li> <Li> John "Doc" Willoughby hosted the Science Desk segment in the show's first two seasons but was gradually phased out during season 3 . After he became executive editor of Gourmet magazine, there was no Science Desk segment for two seasons . John "Doc" Willoughby returned to America's Test Kitchen in 2010 . </Li> <Li> Odd Todd (Todd Rosenberg) designs animations for the Science Desk segment, illustrating such concepts as flambé, brining, marinating vs. dry spice rubs, and whether plastic or wooden cutting boards are better for overall kitchen hygiene . His segments made their debut in season 5 but were replaced by non-animated segments with Jeremy Sauer in season 6 . The animations returned for season 7, interspersed with non-animated science segments done by Kimball and Sauer . </Li> <Li> Guy Crosby is the science adviser for America's Test Kitchen . He began working for Cook's Illustrated as a consulting editor in early 2005 . </Li> <Li> Rebecca "Becky" Hays, Bryan Roof, Dan Souza, Keith Dresser, Elle Simone, Tim Chin and Erin McMurrer are the chefs who explain and prepare the recipes in each episode as the host watches and comments . Usually only one or two of the chefs will appear in an episode . Collin - Davison, Lancaster and Rentschler appeared as regular cast members on season 1 . Since, Rentschler moved to the positions of Culinary Producer and Executive Chef by season 2 and appeared in only one episode that season, before leaving the show by Season 3 . Hays joined the permanent cast in season 5, Bruce, Wu, and Ruperti each appear for a single season (seasons 5, 6, and 8, respectively), and Alt appears in seasons 7 and 8 . All are prominent recipe testers or editors in Cook's Illustrated . Beginning in season 5, Cook's Illustrated staff chefs Hays, Bruce, Jeremy Sauer, and Matthew Card appeared in segments answering common viewer mail questions . Hays, Bruce, and Sauer joined the on - camera cast for season 6; Hays moved into credited cast member status beginning in season 7 . Roof and Souza were added to the regular cast starting season 15 . Chin, Dresser, McMurrer and Simone added to the regular cast starting season 17 . </Li> </Ul>

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