For the purpose of measuring the range of temperature variation of my water bath I poured 14 litres of tap water at 43°C (109.4°F). My target temperature was 58°C (136.4°F).
I approx. need 34 minutes to reach my target temperature which is very long compared to the gaz and halogen stove experiment. This can easely be explained by the 14 litres water to heat compared to 4 litres container I heat with the gaz and halogen stove experiment. The range of temperature variation is of approx. 4 to 5 degrees if you are not taking care. But if you remain close to your water bath and play with the thermostat (see on the graph T5 for thermostat 5…) you can easily remain in a range of 2 degrees. This range of 2 degrees (that could be considered as acceptable) was facilitated by the fact that my container was fed with 14 litres water. Nevertheless you can’t remain close to your cooker if you want to cook a meat for a long period! Therefore cooking sous vide with a basic water bath is not a good option.
I summed up my comments in the table below. Next step will be a SousVideMagic from Fresh Meal Solutions that I purchased on internet some days ago. I should receive it soon!!