Guava Strawberry Jam
Jam is one of those kitchen projects that rewards attention more than technique. This guava-strawberry jam marries the tropical perfume of pink guavas with the bright acidity of strawberries, yielding a spread that’s floral, balanced, and deeply spreadable. It’s an excellent way to preserve a burst of summer when both fruits are at their best.
I make this recipe when I want something pretty on the table but don’t want to babysit a stove for hours. The method uses Pomona’s Universal pectin, which lets the fruit flavor remain the star and gives a clean, dependable set. The recipe also includes small steps—like making calcium water and pressing guava puree through a sieve—that take a little time up front but pay off in texture and clarity.
Keep a rack and a big pot ready, and plan for cooling time after canning. The process itself is straightforward: puree, remove seeds, combine with strawberries, add acid and calcium, boil, stir in sugar + pectin, jar, and process. Read through the ingredients and the step-by-step guide before you begin. That way you’ll move through the work without surprise and end up with jars you’re proud to share.
What Goes In
Ingredients
- 1 ¼ pounds / 1 kg pink guavas — the base flavor; remove stem and blossom ends before chopping for a cleaner puree.
- 1 tablespoon lemon juice — added in the blender to help preserve color and brighten flavor in the guava puree.
- 1 pound / 280 g strawberries, hulled and coarsely chopped — adds sweetness, acidity, and texture; mash lightly for body.
- 3 tablespoons lemon juice — overall acidity to balance the jam and aid proper gelling.
- ¼ teaspoon citric acid — fine-tunes acidity for reliable pectin performance and bright flavor.
- 1 ½ cups / 300 g granulated sugar — sweetens and helps preservation; measured to work with Pomona’s pectin.
- 1 ½ teaspoons Pomona’s Universal pectin — the low-sugar pectin that works with calcium water to set the jam without overcooking the fruit.
- 2 teaspoons calcium water* — activates Pomona’s pectin; follow your pectin kit instructions when preparing this (it’s included with the pectin).
- 1 teaspoon butter, optional — minimizes foaming during the final boil for a clearer jam.
Guava Strawberry Jam Cooking Guide
- Prepare the water bath and jars: Fill a large stock pot or canning pot about 2/3 full with water and place a rack in the bottom. Begin heating the water over medium-high heat so it will be near boiling when the jam is ready. Submerge clean jars (and keep lids and bands hot in the water or in a separate hot container); keep jars hot (hot but not vigorously boiling) until ready to fill.
- Prepare the guavas: Remove stem and blossom ends from 1 1/4 pounds (1 kg) pink guavas. Coarsely chop the guavas and place them in a blender with 1 tablespoon lemon juice. Puree on low speed to avoid pulverizing the seeds.
- Remove seeds and skins: Press the guava puree through a fine-mesh sieve or run it through the fine screen of a food mill to remove seeds and skins. Transfer the finished guava puree to a large, heavy saucepan.
- Prepare the strawberries: Hull and coarsely chop 1 pound (280 g) strawberries, then lightly mash them with a potato masher. Add the mashed strawberries to the saucepan with the guava puree. (Optional: you may blend or food-mill the strawberries with the guavas for a smoother, looser jam.)
- Add acidity and calcium: To the fruit in the saucepan add 3 tablespoons lemon juice, 1/4 teaspoon citric acid, and 2 teaspoons calcium water. Stir to combine.
- Bring fruit to a boil: Heat the fruit mixture over medium-high heat and bring it to a full rolling boil, stirring occasionally.
- Mix sugar and pectin: While the fruit is heating, whisk together 1 1/2 cups (300 g) granulated sugar and 1 1/2 teaspoons Pomona’s Universal pectin in a bowl until evenly combined.
- Add sugar/pectin and finish boiling: Whisk the sugar/pectin mixture into the boiling fruit, stirring continuously until the mixture returns to a full rolling boil. If desired, add 1 teaspoon butter to reduce foaming, or skim foam from the surface.
- Jar the jam: Remove the saucepan from heat and ladle the hot jam into the hot jars, leaving 1/4-inch headspace. Wipe jar rims clean, center lids, and screw on bands fingertip-tight.
- Process jars: Place filled jars in the boiling water bath and process for 10 minutes. Remove jars and set them on a wire rack to cool completely. When cool, check seals; any jars that did not seal should be refrigerated and used within 3 weeks.
Why This Recipe is a Keeper
This jam balances layered fruit notes without leaning overly sweet. Guava brings floral, tropical aromatics; strawberries round out the tart-sweet spectrum and provide familiar jam character. Using Pomona’s pectin means you preserve more of the fruit’s fresh flavor because you don’t have to force the fruit to reduce heavily to set. The result is a bright, aromatic jam that spreads smoothly on toast and melts into yogurt or baking fillings.
Another reason to keep this in your rotation: texture. Pressing the guava puree removes those gritty seeds, which can otherwise overpower the mouthfeel. The small addition of butter is optional, but it helps produce a clear surface without having to skim aggressively. And because the sugar and pectin ratios are modest, the jam feels homey rather than candy-like.
Vegan & Vegetarian Swaps
This recipe is already vegetarian and essentially vegan except for the optional butter. If you want to keep it entirely plant-based, simply omit the butter. The butter only helps with foam control; you can skim foam or let it settle and spoon it off after the final boil.
Toolbox for This Recipe
- Large, heavy saucepan — for even heat and a steady rolling boil without scorching.
- Blender or food processor — to puree guavas gently without pulverizing seeds.
- Fine-mesh sieve or food mill — essential for removing guava seeds and creating a smooth puree.
- Potato masher — for lightly mashing strawberries when you want some texture.
- Measuring cups and spoons — accurate sugar/pectin ratios matter for setting.
- Water bath canner or large stock pot with rack — for safe jar processing.
- Jar lifter and funnel — makes jarring hot jam safer and tidier.
Slip-Ups to Skip
- Skipping the seed removal — guava seeds are numerous and gritty; not sieving them will leave an unpleasant texture.
- Over-blending guavas — puree on low speed to avoid pulverizing seeds; that makes seed removal easier and prevents bitterness.
- Mis-measuring sugar or pectin — Pomona’s system relies on the specified amounts; change them and the set may fail.
- Filling cold jars — cold jars can crack; keep jars hot but not violently boiling, as instructed.
- Skipping the calcium water — with Pomona’s pectin you need the calcium to activate the gelling agent.
In-Season Flavor Ideas
When strawberries are at their peak, keep this recipe as written. If guavas are exceptionally fragrant, reduce the lemon juice by a small fraction to let the guava perfume shine; however, if you adjust acid, re-evaluate the set because acidity affects pectin performance. In late season, when strawberries are softer, mash them a touch less to preserve small fruit pieces. Add a few torn basil leaves during the boil for a savory lift, or fold in a vanilla bean pod for warm notes after jarring (remove the pod before processing if you leave it in while hot).
What I Learned Testing
Take the extra step of passing guava through a sieve. I used to skip it, thinking the seeds would be hidden among the jam’s body; they never were. Once sieved, the jam becomes silky and the guava aroma becomes more apparent. Also, make the calcium water just before you need it; it doesn’t keep well once mixed.
When I tested batches, the sugar and pectin measurements produced consistent sets across different stoves and altitudes as long as I kept a true rolling boil when adding the sugar/pectin mix. That’s why I watch the pot closely during that stage: stir briskly, get the boil back, and time the jar filling. The optional butter does what it promises—reduces foam—so if appearance matters, use it.
Make Ahead Like a Pro
Storing Finished Jars
After processing and cooling, store sealed jars in a cool, dark place for up to a year. Once opened, refrigerate and use within a month for best flavor. Any jars that didn’t seal should go in the fridge and be used within three weeks.
Preparing Components Ahead
You can puree and sieve the guavas a day before, keep the puree chilled, and mash the strawberries just before cooking. Do not mix in sugar or pectin ahead of time; those steps are best done just before boiling the fruit to maintain texture and set reliability.
Your Questions, Answered
Q: Can I substitute other pectins? A: This recipe is written for Pomona’s Universal pectin and its calcium activation. Substituting powdered fruit pectin or liquid pectin will change the acid and sugar requirements and could affect the set. If you must use a different pectin, follow the manufacturer’s directions and expect to adjust sugar or acid.
Q: What is calcium water and how do I make it? A: Calcium water is the calcium solution that comes with Pomona’s pectin. If you’re using Pomona’s kit, prepare it according to the included instructions. If you don’t have the kit, don’t substitute household ingredients—you need the specific calcium concentration Pomona’s formula requires.
Q: Can I reduce the sugar further? A: The sugar level here is calibrated for flavor and shelf stability with Pomona’s system. Reducing sugar may affect taste, mouthfeel, and how long the jam keeps. If you want a lower-sugar preserve, consider refrigerating it and consuming it sooner, and know the set may be softer.
The Last Word
This guava-strawberry jam is about preserving brightness and aroma, not turning fruit into candy. The few careful steps—seed removal, correct pectin activation, and a full rolling boil at the right moment—deliver a clean, fragrant jam that sings on toast, swirls through yogurt, or fills thumbprint cookies. Keep the process organized, follow the exact measurements for pectin and calcium, and you’ll end up with jars that taste like the best parts of summer.
Guava Strawberry Jam
Ingredients
Equipment
Method
- Prepare the water bath and jars: Fill a large stock pot or canning pot about 2/3 full with water and place a rack in the bottom. Begin heating the water over medium-high heat so it will be near boiling when the jam is ready. Submerge clean jars (and keep lids and bands hot in the water or in a separate hot container); keep jars hot (hot but not vigorously boiling) until ready to fill.
- Prepare the guavas: Remove stem and blossom ends from 1 1/4 pounds (1 kg) pink guavas. Coarsely chop the guavas and place them in a blender with 1 tablespoon lemon juice. Puree on low speed to avoid pulverizing the seeds.
- Remove seeds and skins: Press the guava puree through a fine-mesh sieve or run it through the fine screen of a food mill to remove seeds and skins. Transfer the finished guava puree to a large, heavy saucepan.
- Prepare the strawberries: Hull and coarsely chop 1 pound (280 g) strawberries, then lightly mash them with a potato masher. Add the mashed strawberries to the saucepan with the guava puree. (Optional: you may blend or food-mill the strawberries with the guavas for a smoother, looser jam.)
- Add acidity and calcium: To the fruit in the saucepan add 3 tablespoons lemon juice, 1/4 teaspoon citric acid, and 2 teaspoons calcium water. Stir to combine.
- Bring fruit to a boil: Heat the fruit mixture over medium-high heat and bring it to a full rolling boil, stirring occasionally.
- Mix sugar and pectin: While the fruit is heating, whisk together 1 1/2 cups (300 g) granulated sugar and 1 1/2 teaspoons Pomona's Universal pectin in a bowl until evenly combined.
- Add sugar/pectin and finish boiling: Whisk the sugar/pectin mixture into the boiling fruit, stirring continuously until the mixture returns to a full rolling boil. If desired, add 1 teaspoon butter to reduce foaming, or skim foam from the surface.
- Jar the jam: Remove the saucepan from heat and ladle the hot jam into the hot jars, leaving 1/4-inch headspace. Wipe jar rims clean, center lids, and screw on bands fingertip-tight.
- Process jars: Place filled jars in the boiling water bath and process for 10 minutes. Remove jars and set them on a wire rack to cool completely. When cool, check seals; any jars that did not seal should be refrigerated and used within 3 weeks.
Notes
* Calcium powder to make calcium water is included with the Pomona’s brand pectin, other brands of pectin will not require this.
** This recipe requires a low sugar pectin. If using a brand other than Pomona’s, please follow the basic strawberry or guava jam recipe and instructions inside your pectin package, paying attention to the order in which the ingredients are added and the proportion of fruit to sweetener recommended.
