Cannot overcome Coagulation Problem -please HELP!!!

[Sailor Con Queso]

With induction cookers, the milk on the bottom could easily heat too fast and overcook the proteins. If you are stirring properly, temperature gradients won't be a problem.

We use induction cookers every day for making Mother Cultures, yogurt, Mascarpone, and other utilitarian tasks where we need to get milk up to 190F to denature the proteins - and then we use a double boiler setup so we don't have to constantly watch the milk to prevent scorching. But we would never use one to make a hard cheese. In fact, I would never use a stove at all unless I needed a higher temperature for cooking thermophiles. Even then I would do all of the heating up to the cooking phase in a sink with warm water. You are MUCH better off heating your milk in your kitchen sink where it's easier to control the temperature. Too cool - add hot water. Too warm - add cold water and/or remove the pot of milk from the water. I teach all of my students to use a sink instead of a direct heating source.

[qdog1955]

 Sailor, just before your post, I was doing  few experiments-----you are correct-----the bottom is definitely heating up to hot with the induction cooker----I always use the sink for the smaller makes, but when I started making 7 and 8 gallon makes, the weight of milk and vat became an issue---even with the lowered sink-----I have some physical limitations.
  Do you think this is also causing the problems with the floc method?
Will there be less problems heating with the induction cooker using the temperature control mode, that starts at 100 degrees and then steps up to 140 and more----rather then the numbered power mode 1 to 10? Or any other suggestions, because I really like the induction cooker and maybe just need to fine tune it's use.
  Thanks for your input.
Qdog

[Sailor Con Queso]

Qdog. There are many different types of induction cookers with varying methods for controlling temperature. In general, the numbered control mode is really erratic and inappropriate for cheese making. Temperate mode can work depending on the induction cooker. Our main cooker can only go down to 140F, but we use it every day. I have another cooker that goes down to 100F with 10 degree increments - 110, 120, 130, etc. I actually use that cooker for sous vide style cooking and I find that it will hold temperature to within 2-3 degrees, IF you don't put the lid on the pot. With the lid on, it can vary 8-10 degrees. That's because induction measures surface temperature NOT inside the pot.

I would strongly suggest that you try to use a double boiler - pot-in-pot - setup and stir frequently to equalize temperature. Before you add the rennet, the induction cooker MUST be turned off. Otherwise you will be adding excess heat to the bottom of the pot and the milk.

A 7-8 gallon make is 60-70 pounds and an awful lot for an induction cooker. If your pot is hanging over the element you can get uneven heating.

[John@PC]

Whatever the problem is / was with the curd quality gradient you NEVER want to heat un-cut curds in any way, shape of fashion!   I've screwed up enough batches leaving heat on after adding rennet and I found out that heat dispersion within a semi-solid (coagulating curd) is a whole lot less than a liquid  . 

Sailor:  I posted this before reading yours and I think we're saying the same thing.  Sorry for repeating what you said but is an important point especially for those of us learning how to make cheese.

[OzzieCheese]

I too have made that mistake early on..  turned the curd to crud - Oooo I made a funny......

-- Mal

[Kern]

Whatever the problem is / was with the curd quality gradient you NEVER want to heat un-cut curds in any way, shape of fashion!   I've screwed up enough batches leaving heat on after adding rennet and I found out that heat dispersion within a semi-solid (coagulating curd) is a whole lot less than a liquid  . 

John, you are absolutely correct.  Prior to coagulation the milk transfers heat by convection, which is to say rather effectively for a thin liquid.  Once gellation occurs the convection path is effectively blocked and the heat transfer occurs through conduction.  If the heat source is much hotter than the milk temperature the milk in the bottom of the pan will get hot very quickly through the high heat transfer rate of thin stainless steel.  One should make sure that the heat source is at the milk temperature when the rennet is added to the milk (or remove the milk in the case of a double boiler containing hot water.  It is much better to accept a drop of several degrees before curd cutting than trying to maintain the goal  temperature by adding heat to the system.