Sous Vide using polycarbonate pot

[Qari]

Decided to test out a sous vide setup using a polycarbonate container I already had for the milk.  This would allow me to make larger batches of cheese if successful.  My stainless steel pot holds 2 gallons, while the polycarbonate container holds 3 gallons.  My concern was the ability of the water bath to heat up the milk in the polycarbonate.  I chose to attempt a gruyere style cheese following Caldwell’s recipe pretty closely.  Unfortunately, my concerns about the ability of the water bath to heat milk in a polycarbonate container proved to be true. I found I needed to heat the water bath quite a bit warmer than my goal temp in order to heat the milk. 

I started by putting the gallon bottles of milk in the sink with hot water to jump start the heating process while I set up and sanitized my equipment.  I used star san on my polycarbonate container and boiled/steamed the rest of my equipment.  The hot water in the sink heated the milk to 80F.  It took about an hour to heat the milk to 90F since the water bath was only at 100F.  Proceeded with adding cultures, CaCl and rennet as usual.  Got flocculation at 12 minutes and used a multiplier of 2.5.  Got a nice clean break 30 minutes after adding rennet.  Cut the curd into 1/4 inch cubes, let rest for 5 minutes, then used a whisk to slowly cut to 1/8 inch.  The next step was to scald the curd with slow stirring, heating to 118-123 F over 1 hour with a goal pH of 6.35.  This was taking so long  I ended up having to increase the water bath to 140F.  I got the milk to 116F after 80 minutes before reaching pH of 6.36.  I decided to go by pH, rather than temp/time and hooped the curd. 

Started with very light weight (abut 5 lbs).  Found I needed to increase the weight to 10 then 20 lbs with subsequent flips to get the curt to knit well. Not surprising since the curd was probably drier due to prolonged scalding.  Ended up pressing with 30 lbs.  Brined for 9 hours in heavy brine once pH reached 5.35.  Planning on trying a washed rind. 

[awakephd]

Susan, congrats on a successful make in spite of having to work with uncertain variables!

There have been a lot of claims and counter claims about the safety of polycarbonate and food, particularly at elevated temperatures. I wouldn't think even 140° would be hot enough to generate much migration of the BPA, but since it turned out not to work so well for heat transfer anyway ... I'd say it's time to look for a stainless container.

[scasnerkay]

That is a lot of water to heat!
The difference in size between my water container, and milk container is quite small. There is room in one corner for the sous vide heater.
I find the set up works well for tomme, Gouda, cheddar, Caerphilly. And also for Asiago fresco and Montasio. Those are heated to 102 or to about 118 in my makes.
I usually set the unit about 2 or 3 degrees warmer than the target, and get there in a timely manner.
I did find that the sous vide unit could not lift the temp of 5 gallons of milk for a thermophyllic make.
I think you would have lost a lot of heat off h Th e surface of the water - it is a large uncovered area.
I do really like the sous vide for the makes!!

[tcoop]

Decided to test out a sous vide setup using a polycarbonate container I already had for the milk.  This would allow me to make larger batches of cheese if successful.  My stainless steel pot holds 2 gallons, while the polycarbonate container holds 3 gallons.  My concern was the ability of the water bath to heat up the milk in the polycarbonate.  I chose to attempt a gruyere style cheese following Caldwell’s recipe pretty closely.  Unfortunately, my concerns about the ability of the water bath to heat milk in a polycarbonate container proved to be true. I found I needed to heat the water bath quite a bit warmer than my goal temp in order to heat the milk. 

I started by putting the gallon bottles of milk in the sink with hot water to jump start the heating process while I set up and sanitized my equipment.  I used star san on my polycarbonate container and boiled/steamed the rest of my equipment.  The hot water in the sink heated the milk to 80F.  It took about an hour to heat the milk to 90F since the water bath was only at 100F.  Proceeded with adding cultures, CaCl and rennet as usual.  Got flocculation at 12 minutes and used a multiplier of 2.5.  Got a nice clean break 30 minutes after adding rennet.  Cut the curd into 1/4 inch cubes, let rest for 5 minutes, then used a whisk to slowly cut to 1/8 inch.  The next step was to scald the curd with slow stirring, heating to 118-123 F over 1 hour with a goal pH of 6.35.  This was taking so long  I ended up having to increase the water bath to 140F.  I got the milk to 116F after 80 minutes before reaching pH of 6.36.  I decided to go by pH, rather than temp/time and hooped the curd. 

Started with very light weight (abut 5 lbs).  Found I needed to increase the weight to 10 then 20 lbs with subsequent flips to get the curt to knit well. Not surprising since the curd was probably drier due to prolonged scalding.  Ended up pressing with 30 lbs.  Brined for 9 hours in heavy brine once pH reached 5.35.  Planning on trying a washed rind.

Most plastics are very poor conductors of heat, polycarbonate is better than many others but is terrible in comparison to any metal pot.