About The Jam Scientist and The Professor

Strawberry Jam: It Isn't Just for June Anymore - Inaugural Issue of Best Little Jam House

Albion Strawberry Jam
Albion Strawberry Jam is the stuff that dreams are made of.

I have been waiting all year to make some fall strawberry jam. Strawberry jam is not just for June anymore. My preferred strawberry, 'Albion,' is a long and thin, day neutral strawberry  that begins showing up in the fruit stands toward the end of summer and availability should continue at least until end of October! You can smell  Albion's berry fragrance from ten feet away from the fruit stand, and when you taste them you won't forget the sweet surprise. Other day neutral strawberries may taste good, but Albion has spectacular flavor! 

Albion Strawberry Jam is the stuff that dreams are made of - perfect for jam making and Christmas gifts! I have adapted one of Christine Ferber's French strawberry jam recipes to produce a thicker, more American style jam by using commercial pectin. Strawberries have little natural pectin so one must either add pectin, learn to enjoy a more syrupy consistency, or cook them until they are somewhat caramelized. Don't worry; we will also make some French style jam in our next issue. If you don't have day neutral berries for sale in your area you can use frozen berries.

First, I will be sharing just the recipe for making jam.  If you need information about the basic canning process please click here.

For those new to canning, please note that it is important not to make changes to the recipe.  Proportions are important and must be maintained for success. It is also not advisable to double the recipe because larger volumes would slow evaporation and affect the fresh flavor we want.

 If you would like to print the recipe without all the pictures please click here Download American Style Strawberry Jam Recipe

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                   Strawberry Jam Recipe

Prep time: 

24 hours


Processing time: 

10 minutes for half pints


Cook time: 

30 minutes



4 or 5 half pints (half pints = 1 cup)


Total time:

24 hours, 30 minutes

   Head Space:  1/4 inch    


  • 2½+ pounds fresh strawberries (2 1/3 lb after hulling and slicing)
  • 4 cups granulated cane sugar (825 grams, or 1 lb, 13 oz)
  • Zest and juice of one large lemon 
  • One pouch liquid pectin
  1. Wash, dry, hull, and slice your strawberries. Place the strawberries into a large nonreactive (glass or stainless) bowl. Stir in the sugar and the lemon juice.


Start of maceration
Let strawberries sit to extract juice

2.   Let strawberries sit (macerate) to extract juices - 2 hours, covered, at room temperature. Simmer strawberries in a wide-bottomed pan, or a preserving pan, just until sugar melts.

Strawberries in preserving pan.
Simmer strawberries just until sugar melts

3.   Pour mixture into a nonreactive bowl. Cover with parchment paper and store in the refrigerator to extract juices (macerate) overnight.

4.   Next day, pour the contents through a sieve or strainer to collect juice and separate berries.

5.    Bring just the collected syrup to a full rolling boil,and continue cooking on high heat until a candy thermometer reaches 221 degrees (The syrup will be sufficiently concentrated at 221 degrees [105 degrees C] on a candy thermometer).

Strawberry syrup boiling
Strawberry syrup boiling on high heat

6.   Meanwhile, set up your water bath canner, sterilize your jars, and warm your lids in a pan of warm water.

 7.    Stir one packet liquid pectin into the strawberries and quickly blend. Add strawberry mixture to the hot syrup. Mash about 1/4 of the berries. Return mixture to a boil on high heat.

strawberries and hot syrup
Blend strawberries and hot syrup.

8.   Return syrup and berries to a full rolling boil. Boil for just one minute, stirring gently. Check the set at one minute. You can do this by using the sheet or plate test. If the jam is still runny, cook another minute and test it again.

9.   Let the jam cool for 5 minutes before skimming off foam and ladling jam into hot jars. This cooling time prevents the berries from separating in the jar (this is important - otherwise berries will float to top of jar).


intensely flavorful Strawberry Jam
You won't forget the intensely flavored sweet surprise.

10.    Pour the jam into sterilized hot jars leaving 1/4 inch head space. Transfer to boiling water bath and process for 10 minutes if using half-pint jars, or 15 minutes if using pint jars.

Note: Processing time given is for 1000 foot elevation and below. If you are working at a higher elevation click here for information about needed time adjustments.

Jam will last at least one year at peak quality.

I suggest you label your jam jars. One may simply write on the lid, or you may download my labels here Download Strawberry Jam round label. My labels have a larger round label for the lid and a smaller oval label for the front of jar. One just needs to write in the canning date, cut out, and glue the label on the jar.

The Professor's Rating

The professor gave it 4 stars.  He ate a jar up in two days saying "that's good jam"... It earns a place in our pantry.


Albion Strawberry Jam Demystified

Jam scientist's notebook coloredHow do I know this recipe is safe? pH, Water Activity, and Heat

pH  - To be safe from botulism bacteria growth and its food poisoning toxins, the pH of canned goods must be below 4.6 (one wants to stay below pH 4.4. to be on the safe side). Strawberries are generally between pH 3.0 and 3.9. We added some lemon juice to the recipe so the jam should be between pH 3.0 and 3.4 - well within the safety zone.

Water activity - We also added sugar in this recipe. Salt and sugar "hold onto" water very well and therefor the water is not usable to bacteria for growth. The measurement of how much water is available for microbes' growth is called water activity or aw. A water activity of 0.85 or less is considered the safe cutoff level for deterring pathogen growth (however, yeasts and molds can still grow at at this level). Traditionally made jams (like the one we just made) have a water activity of between 0.75 - 0.80 - so we have additional protection from bacteria growth because of the sugar. Traditional jams will last almost twice as long as low sugar jams because of their lower water activity, and they are safe for longer times out of the refrigerator.

Heat - Processing the jars in a boiling water bath for 10 minutes is enough heat to kill actively growing bacteria and prevent yeast and mold growth under normal sanitary circumstances. This is how we control the yeasts and molds that were not affected by the low pH or moderately low water activity.

What is maceration?

The sugar added to the berries will pull  the natural juices from the berries and create flavorful syrup. This way you will not need to add water to the recipe, and will not dilute the taste. It is interesting to note that in this context the amount of sugar you add helps determine the amount of liquid in the final product and how concentrated the flavor will be.

Why cook the juice first?

Heat is the enemy of flavor. By heating the juice first you quicken the cooking process for the berries and end up with a fresher tasting jam. Also, usually recipes using liquid pectin would call for 7 cups of sugar per batch. That much sugar would reduce the flavor of the jam because the berries would be more diluted. By concentrating the juice (and concentrating the sugar in the juice) by evaporation we can get away with using less sugar when using liquid pectin.





















The Jam Scientist


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