Strawberry Rhubarb Preserves

Strawberries were early this year and it has given me way too many opportunities to pick some up from local farmers.  I end up with way too many and have to find ways to keep them from spoiling.  I've made strawberry sauce (I've been making it a couple years now after a failed no pectin strawberry jam experiment).  I don't like to add pectin to my jams and preserves so this combination works really well.  The rhubarb and lemon give enough pectin to thicken these.
As a bonus the tartness of rhubarb and brightness of lemon pair great with sweet strawberries....

makes 8-10 pints depending on how long you cook it

6 cups sliced strawberries, large pieces
6 cups rhubarb, cut large ~1/2"
2 lemons, cut in thin slices and seeds removed
3 1/2-3 3/4 cups sugar, depending on how sweet strawberries are
1/2 TBS vanilla, optional

Wash the strawberries and remove stems.  Slice and add to a large stock pot with a thick bottom.  Wash rhubarb, slice and add to pot.  Add the slices of 2 lemons, cut slices in half. 
Add 3/4 cups of water and bring to a boil over medium high heat, simmer for 10 minutes. 
Add sugar and vanilla and return to a boil, then reduce heat to medium low and simmer for about 30 minutes or until somewhat thick.  It will thicken more as it cools.
You can do the freezer test at this point to check if it is the consistency you want.  Just place a small plate in the freezer until it gets cold, remove and place a spoon of preserves on plate and place back in freezer for 2 minutes.  When you remove plate from freezer nudge the preserves a bit with your finger, if it is thick and jam like then you have reached the consistency of typical preserves/jams.  If you like it thicker then continue to cook.

Now place in sterilized jars and follow safe canning methods for long term storage or place in the refrigerator and use soon.
I can these in a hot water bath and remove from after 10 minutes of hard boiling.

Strawberries, rhubarb and lemon in pot before boiling