How to make feijoa jam?

Every year around late October here in San Diego, my backyard transforms into a minefield of green, egg-shaped grenades. If you grow Feijoa sellowiana, commonly known as the pineapple guava or guavasteen, you know exactly what I’m talking about. One day the tree is quiet, and the next, you are tripping over pounds of fallen fruit that perfume the entire yard with a scent somewhere between a flower shop and a candy factory.

Emily Rodriguez

Here at Exotic Fruits and Vegetables, we've found that the sheer volume of a feijoa harvest often overwhelms new growers. You can only eat so many fresh out of hand before your tongue starts to hurt from the acidity. That is when the canning kettle comes out.

Making feijoa jam isn’t just a way to save the fruit; it captures that fleeting, complex flavor profile—strawberries, pineapple, and mint—in a jar you can enjoy when the marine layer rolls in during June.

The smell of a ripening feijoa is the only timer you need; if you can smell it from ten feet away, it’s ready for the pot.

I’m going to walk you through my personal method for turning these green gems into liquid gold. This isn’t a generic recipe; this is the result of sticky floors, burnt sugar, and years of refining the process right here on my farm. We will cover everything from the tedious prep work to the final water bath.

Understanding Your Ingredients

Before we fire up the stove, we need to talk about the fruit itself. The feijoa is technically a berry, and unlike other guavas, its skin is bitter and tough. For a premium jam, we only want the creamy, gelatinous center and the gritty flesh surrounding it. We leave the skins for the compost pile.

The Pectin Equation

Feijoas are moderately high in pectin, but the level drops as the fruit over-ripens. Since we only harvest feijoas after they drop from the tree (never pick them!), we are usually working with fruit at peak ripeness or slightly past it. This means we cannot rely solely on the fruit’s natural thickening power.

Pectin acts like the structural steel in a skyscraper; without enough of it, your jam will just be a delicious, runny syrup.

Through our work with Exotic Fruits and Vegetables farm, we have experimented with low-sugar pectins versus natural reduction. I prefer using a standard high-methoxyl pectin or simply reducing the jam longer if I have the time. However, for this guide, we will use a specific ratio of sugar and lemon juice to ensure a set without commercial additives, relying on the fruit’s natural biology and evaporation.

The Golden Ratio

Jam making is chemistry, not art. You cannot eyeball the sugar and expect good results. Sugar does more than sweeten; it bonds with the water molecules, forcing the pectin chains to bond with each other. Here is the breakdown of what actually works in my kitchen:

Step-by-Step Production Process

I once ruined an entire batch by trying to blend the skins into the jam to save time. The result was a bitter, muddy green paste that tasted like medicinal herbs. Don’t cut corners. Put on some music, because you are going to be scooping for a while.

1. Extraction and Maceration

Wash your feijoas thoroughly to remove any garden soil or pests. Slice each fruit in half vertically. Using a sharp teaspoon, scoop the flesh into a large, non-reactive bowl (stainless steel or glass). You must measure the fruit after scooping, not before, to ensure your chemical ratios are correct. Once you have 4 cups of pulp, pour the sugar over the fruit and let it sit for 45 minutes. This process, called maceration, draws the juices out of the fruit cells, dissolving the sugar before you even turn on the heat.

Macerating your fruit reduces cooking time significantly, preserving that bright, fresh “tutti-frutti” flavor that heat destroys.

2. The Hard Boil

Transfer your sugary fruit mixture into a wide, heavy-bottomed pot. A wide pot increases surface area, allowing water to evaporate faster. Add your water and lemon juice now. Bring the mixture to a rolling boil over medium-high heat. You want a boil that doesn’t stop bubbling when you stir it.

1. Mash the fruit: As it boils, use a potato masher to break down the larger chunks. I like leaving some texture, but you don’t want whole halves floating around.
2. Skim the scum: You will see a pinkish-white foam rising to the top. Skim this off with a ladle. It’s harmless denatured protein, but it clouds your clear jam.
3. Monitor the temp: Clip a candy thermometer to the side of the pot. We are aiming for the magic number: 220°F (104°C).
4. Stir constantly: As the mixture thickens, it becomes a volcano. Hot sugar burns are nasty, so wear long sleeves.

Never leave a boiling jam pot unattended; it takes exactly ten seconds to go from “simmering nicely” to “boiling over and fusing to your stove.”

What’s the real secret to success? Patience during the final five degrees. The jam will stall at 212°F (the boiling point of water) until most of the water is gone. Only then will the temperature climb to 220°F. This can take anywhere from 20 to 40 minutes depending on your humidity.

Canning and Storage

Once you hit 220°F, remove the pot from the heat immediately. If you are planning to eat this within three weeks, ladle it into clean jars and shove them in the fridge. But if you want to store the harvest for winter, you need to water bath can it.

I sterilize my jars by running them through the dishwasher on the hottest cycle right before cooking. Fill the hot jars with hot jam, leaving 1/4 inch of headspace at the top. Wipe the rims with a clean, damp paper towel—any sticky residue will prevent a seal. Screw on the lids fingertip tight.

Do not overtighten the bands before processing; air needs to escape from the jar during the boiling phase to create a vacuum seal.

Process the jars in a boiling water bath for 10 minutes (adjusting for altitude if you live in the mountains east of San Diego). Turn off the heat and let them sit in the water for 5 minutes before removing. You should hear the satisfying “ping” of the lids sealing within an hour.

Troubleshooting Common Issues

Even with experience, things go sideways. Our team at Exotic Fruits and Vegetables loves analyzing why a batch failed so we can fix it next time. Here are the most common issues I see with feijoa jam:

• The Jam is Runny: You didn’t boil off enough water, or the fruit was too ripe and low in pectin. You can re-cook it with a tablespoon of powdered pectin.
• Crystallization: This happens if undissolved sugar crystals on the side of the pot get stirred back in. Use a wet pastry brush to wipe down the sides of the pot during cooking.
• Fruit Floats to Top: You didn’t crush the fruit enough, or you jarred it while it was too hot and fluid. Stirring the jam for 5 minutes off the heat before jarring helps distribute the fruit.
• Mold Growth: Your seal failed, or the acid level was too low. Lemon juice is non-negotiable for safety; it prevents botulism and inhibits mold.

Flavor Variations

Once you master the basic recipe, you can get creative. I recently added a thumb-sized piece of grated fresh ginger to a batch, and the spicy heat paired perfectly with the floral notes of the feijoa. Another favorite in my house is adding a split vanilla bean during the boil. It rounds out the sharp acidity and makes the jam taste like a fancy dessert topping.

Ever wonder why store-bought jam never tastes as vibrant? It’s because mass production cooks the fruit to death, killing the volatile aromatic compounds.

Enjoying Your Labor

Making feijoa jam is a labor of love. It requires standing over a hot stove when the San Diego Santa Ana winds might already be heating up your kitchen. But when you spread that emerald-green preserve on a piece of sourdough toast in January, the effort pays off. The flavor is a concentrated burst of the previous season’s sunshine.

I usually get about 5 half-pint jars from the recipe above. It makes for incredible holiday gifts, assuming you can bear to part with them. Store your sealed jars in a cool, dark pantry for up to one year, but once opened, keep them refrigerated.

As fruit enthusiasts at Exotic Fruits and Vegetables, we believe growing food is only half the battle; knowing how to preserve it is what makes you a true farmer.

Pro Tip: To test the set without a thermometer, put a plate in the freezer before you start cooking. Drop a spoonful of hot jam on the cold plate; if it wrinkles when you push it with your finger, it’s done.

So, next time you hear the thud of a feijoa hitting the ground, don’t groan about the cleanup. Grab a bucket, sharpen your spoon, and get ready to make the best jam you’ve ever tasted.