How do you determine if a food is high or low acid for canning purposes?
I want to can salad dressing that has oil, vinegar, lemon juice, tomato paste and spices in it. I have no experience canning so I looked it up online and found that high acidic foods can be jarred in a hot water bath, while low acid foods need a pressure cooker. How do I determine which to do? Also, will heating it change the flavor and composition of the food?
Thank you!
Can something with oil be canned?
July 7th, 2010 at 7:35 pm
By determining the ph
July 7th, 2010 at 7:45 pm
You can purchase a pH meter for determining the foods pH or acidic level.
http://www.professionalequipment.com/ph-meter/
http://en.wikipedia.org/wiki/PH_meter
Much more practical: Strips
http://www.ph-ion.com/index.asp?PageAction=VIEWPROD&ProdID=9
http://www.evenbetternow.com/proddetail.asp?prod=ph_litmus_test_paper_strips&s=positiontech3
http://www.pickyourown.org/food_acidity_ph_list.htm
http://missvickie.com/canning/whatisacid.html
http://ohioline.osu.edu/hyg-fact/5000/5338.html
http://www.ext.nodak.edu/food/lemnjuic.pdf
Also, will heating it change the flavor and composition of the food?
YES
The very definition of cooking (with heat) is to change the foods flavor and composition. You can learn to control the foods flavor and composition for each specific food item with practice.
Good luck.
July 7th, 2010 at 7:59 pm
By determining the PH. Here’s a link to the USDA canning web site:
http://www.uga.edu/nchfp/publications/publications_usda.html
July 7th, 2010 at 8:42 pm
Vinegar, lemon juice and tomatoes are highly acidic.
If you ever make a dressing with milk or cream, then you could end up with a low acid or alkali product. When in doubt, us some PH-litmus paper as used in for aquarium water (pet store).
July 7th, 2010 at 9:15 pm
It is not recommended to can anything containing oil, the oils prevent the heat from killing any botulism spores or other bacteria that may exist in the product. Any canning with oil added should be done with a hot water bath and must have something added to make the solution fairly acidic (5% vinegar) But it is not a practice that is advised on any canning website because of the chance it might become rancid.
High-acid foods such as tomatoes, fruit, and pickles process in a boiling waterbath canner.
All fresh vegetables except for most tomatoes are low-acid foods. Other low-acid foods are red meats, seafood, poultry and milk, you can use a pressure cooker to preserve these foods.
Yes heating can change the flavor and composition of certain foods. For the most part you really will not notice it.