Published March 2nd 2012
- Size and weight: Polyscience SV Professional is more heavy compared to SV Chef of Vacstar. Proportions and design of both circulators are very similar. You can say Vacstar was not really inspired when copying Polyscience’s design. Even small details are similar but the finishes of VcaStar are not neat and the quality of the plastic used by Polyscience is far better. The big difference in weight could be explained by a more powerful motor used by Polyscience to mix water.
- Tank/vessel capacity: Polyscience and Vac-Star have designed their immersion circulator for a similar vessel capacity (20 L). Polyscience indicates SV Professional can stabilise water up to 30 L.
- Safety: a float switch is the best solution to alert cooks when the waterlevel is too low and pouches risk to float at the surface. SV Chef of Vac-Star benefits from this safety device, Polyscience don’t. The float switch of Vacstar is made of plastic and foam (see picture) that looks cheap compared to the metal float switch proposed by other trademarks. The overheating protection of Polyscience has not been implemented for food safety reasons but to protect the machine against fire in the case of low waterlevel. We made a test removing water below the “min” water level until the pump was not runing in water anymore. The SV Chef of Polyscience was still running and keeping the coil temperature as close as possible to the target temperature.
- Temperature stability: Polyscience SV professional has an exceptional stability (± 0.06°C) which can be achieved especialy if containers are well insulated. Vac-Star SV Chef is using an On/Off controler as discussed in this interesting Egullet forum. This “technology” is wellknown since Seattlefoodgeek.com blog has developped a $85 DIY immersion circulator. Some well informed poeple on Egullet pointed out that such equipment can’t last long because of a mecanical relay that could break : “… Assume a 1 million cycle life and 10S period. Relay life would be 1M cycles * 10S period/ 3600S/Hr = ~3000 Hrs of operation. Maybe longer if you increase the period or start skipping cycles entirely when you reach equilibrium… if you use a relays it will not break for some time when controlled “correctly” (though even 3000h are not that much considering the 72h cooking marathons those device have to withstand). I would not use one because of the scenario that might happen when the relays malfunctions and gets stuck, and the heating element run continuously on full power”…
- Ease of use, comfort, silent: both immersion circulators are easy to use. Polyscience doesn’t have a timer. Vacstar has one but it is not really user friendly. Buttons of Vacstar are a bit too small in my opinion. Polyscience SV Professional is loud because of its big motor while Vac-Star SV Chef is silent but less powerful.
- Maintenance, cleaning: immersion circulators must be frequently cleaned to remove the limescale appearing after some days of intensive use on the grid and heating coil. A sous vide pouch could also break during cooking process (badly sealed pouch). You need a screw driver to open the plastic grid and clean the device. The VacStar SV Chef is a little bit less practicle to open and to close compared to Polyscience. In my opinion both Polyscience and Vacstar heating coils are not easy to clean. The float switch of VacStar is cheaply made of plastic and foam. If not cleaned often this float switch may get stuck.
- Warranty: 1 year.
- Price: SV Professional of Polyscience is twice more expensive compared to SV Chef of Vac-Star (EUR 625 excl.VAT EUR compared to 285 excl. VAT).
- Polyscience immersion circulator is well designed and a wellknown American trademark. It contains the state of the art PID controler and gives a great feeling of confidence when having it in your hands. On the other hand SV Professional doesn’t have a timer, a float switch and is made of plastic, probably for costs reasons.
- Vac-Star has launched the cheapest immersion circulator available on the market but can’t be compared, in terms of technology and quality, with Polyscience. It works fine but it seems the technology used by VacStar to control the temperature (a mecanical relay) has a limited life expectancy.