I was doing a mass blanching of around 30 lbs of asparagus I got for 88 cents a pound today. I did not have alot of ice to use for the blanching and did not want to go to the store. I had 4 glass containers of chicken stock the size of small loaves of bread in the freezer so I used these to put in the sink for ice water. One good idea I picked up on the net for blanching is to use two water vessels, one for the first cooling and a second for the final. The first vessel does most of the work and gets changed often. I love this great idea. My questions regarding blanching are as follows: 1. Is the above idea good, does partial defrosting of the stock hurt anything? 2. Would you need to add time when blanching at high altitude as water boil at a lower temp? 3. Is there any clear cut way to see if your blanching is done correctly? 4. I assume it is wise to change the boil water when doing long blanching runs like I did tonight (approx 30 1 lb batches). When I find food on sale I love stocking up and getting into these mass production assembly line situations. Got me hypnotized.