About canning pumpkin

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OK I have a new question about canning pumpkin butter, I have always canned pumpkin butter in the pressure cooker, and for 90 minutes at 10 lbs. Does anyone know if you have to pressure can pumpkin, or pumpkin butter? It just takes so long. Help.... Apple butter can be processed in a hot water bath for 15 to 20 minutes, but everything I have read, and there is not much says pressure cook pumpkin.

-- Beth Susan Craig (Criag@icu2.net), October 10, 1999


Pumpkin is a low-acid food, and all low-acid foods must be pressure canned to prevent spoilage. Thats just the way it is.

-- Sam Mcgee (weissacre@gwtc.net), October 10, 1999.

Well...here's another viewpoint!


Canning Pumpkin Butter and Mashed or Pureed Squashes

University of Georgia

Home canning is not recommended for pumpkin butter or any mashed or pureed pumpkin or winter squash. In 1989, the USDA's Extension Service published the Complete Guide to Home Canning that remains the basis of Extension recommendations today, found in the September 1994 revision. The only directions for canning pumpkin and winter squash are for cubed pulp. In fact, the directions for preparing the product include the statement, "Caution: Do not mash or puree."

In accordance with the USDA recommendations, the University of Georgia Cooperative Extension Service does not have a recommendation for canning these products either. There are not sufficient data available to allow establishing safe processing times for any of these types of products. It is true that previous USDA recommendations had directions for canning mashed winter squash, but USDA withdrew those recommendations and any publications preceding the Complete Guide to Home Canning (September 1994) are considered out of date.

Some of the factors that are critical to the safety of canned pumpkin products are the viscosity (thickness), the acidity and the water activity. Studies conducted at the University of Minnesota in the 1970's indicated that there was too much variation in viscosity among different batches of prepared pumpkin purees to permit calculation of a single processing recommendation that would cover the potential variation among products (Zottola et. al, 1978). Pumpkin and winter squash are also low-acid foods (pH > 4.6) capable of supporting the growth of Clostridium botulinum bacteria which can cause the very serious illness, botulism, under the right storage conditions. If the bacteria are present and survive processing, and the product has a high enough water activity, they can thrive and produce toxin in the product.

More recent research with pumpkin butter has been done at the University of Missouri. Pumpkin butter is mashed or pureed pumpkin that has had large quantities of sugar added to it, but not always enough to inhibit pathogens. Sometimes an ingredient such as vinegar or lemon juice is added to the formulation to increase the he acidity (decrease the pH). However, pumpkin butters produced by home canners and small commercial processors in Missouri have had pH values as high as 5.4. In fact, the pH values seemed to be extremely variable between batches made by the same formulation (Holt, 1995).

It is not possible at this point to evaluate a recipe for pumpkin or mashed squash for canning potential by looking at it. At this point, research seems to indicate variability of the products is great, and in several ways that raise safety concerns. It is best to freeze pumpkin butters or mashed squash.


1.Extension Service, USDA. 1994. Complete Guide to Home Canning. AIB No. 539. U.S. Department of Agriculture, Washington, DC. 2.Holt, D. September 22, 1995. Re: Pumpkin Butter. Email message to fnspec_mg@ecn.purdue.edu. 3.Zottola, E. A., Wolf, I.D., Norsiden, K.L. and Thompson, D.R. 1978. Home canning of food: Evaluation of current recommended methods. Jn. of Food Science 43:1731.

-- Got Libby's? (Libby@thelabel.ugh), October 10, 1999.

Have you considered dehydrating pumpkin? That method is known to be safe and used to be the way preservation was done.

-- helen (sstaten@fullnet.net), October 10, 1999.

I thank you for the info on pumpkin butter. Best thing for me to do is leave the pumpkin butter alone. I will just use solid pack pumpkin already canned and make up just enough for my family to use a little at a time.

I only have the no fan type of drying machine. The does not cost too much money type, and have not tried to dry much yet. The one time I did try to dry apples I know I overdried them, they were little rocks. I need lots of help with drying and storage of dried things, It does not help too much if they are too hard to eat. In return here is a old recipe for Black Walnut Pound Cake

1/2 cup shortening 1 cup of Butter or margarine 3 cups of sugar 6 eggs (yes I said 6) 3 cups of plain flour 1/2 teaspoon salt 1/2 teaspoon baking powder 1 cup milk 1 teaspoon of vanilla 3 tablespoons Black Walnut extract. (must be extract, or use more flavoring 1 & 1/2 cups chopped walnuts.

Cream butter and shortening together till smooth. add sugar a little at a time, cream till looks like whip cream. (this is important for pound cakes to cream butter and sugar together.

Add eggs one at a time beat a little after each one.

In a bowl sift flour, salt, and baking powder together,

In a large cup, or small bowl add milk, and flavoring together.

Pour flour in mixer while it is on as low a speed as it will go. You may add a little milk with this if it gets too thick. finish adding all of the milk. mix well, and add walnuts.

Have a tube pan well greased (no spray pam) and line with a wax paper botton, or brown paper bag. To do this turn pan upside down lay paper over bottom of pan and take the edge of a knife and run around the edge using the flat side of the knife to make a scratch mark on the paper, cut out and lay in botton of greased pan, grease top of paper, when you take cake out peal paper off, no stuck cake, all you have to do is run a knife around the side and tube of the pan.

Ok preheat oven to 325 degrees and bake on center rack for around 1 hour and 15 minutes. check with a knife or straw. When cake comes out of oven wrap in foil while still hot to make moist.

Hope you enjoy, this is one of my family's fav. cake.

-- Beth Susan (craig@icu2.net), October 11, 1999.

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