Why Is My Lemon Bitter? Answered!

Lemon is a versatile fruit and one that I enjoy growing in my garden. It adds flavor to dishes and baked goods and makes a delicious natural flavoring for water. However, sometimes I use lemon slices in a recipe or add some to my drinking water only to find that it has a bitter taste. So why does that happen with some lemons but not all of them? Keep reading to learn more about why your lemon tastes bitter and what you can do to fix it.

Fresh lemons on a wooden table.
Lemons on a wooden table.

Why Is My Lemon Bitter?—The Short Answer

Lemon should have a sour and acidic taste that sweetens when mixed with sugar. If you squeeze a lemon for juice or use lemon slices in a recipe and discover that it tastes bitter, it most likely has to do with the rind (pith), the lemon’s ripeness, or that the lemon has started to go bad. If you’re growing your own lemons, a horrible taste could also have to do with the growing conditions.

How the Pith of the Lemon Skin Affects the Lemon’s Taste

The Pith And Bitterness

All fruits in the citrus family, like lemons, oranges, and limes, have a spongy white tissue that lines the inside of the outer skin (known as the rind). Although the rind of the lemon does not taste bitter (as many dessert recipes call for grated lemon rind), the pith has a very bitter taste due to a large amount of a compound called glucoside hesperidins.

Sometimes, when you squeeze a lemon to extract the juice, you inadvertently squeeze it a bit too hard, and the pith mixes into the juice a bit, causing bitterness. This issue is the most common reason you may have a bitter taste in your water after squeezing fresh lemon juice into it, or your fresh lemonade could have a bitter taste. 

How to Reduce Lemon Pith Bitterness When Squeezing

To reduce bitterness caused by the pith entering the lemon juice while squeezing, try to squeeze the lemon as gently as possible. Alternately, you can remove the rind and the pith from the lemon before squeezing it to prevent this issue. If that step seems too much work, try using a citrus juicer. This tool comes in both manual and electric versions and squeezes the lemon so that it significantly reduces the amount of pith that gets into the flesh and juice of the lemon.

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Cuisinart CCJ-500P1 Pulp Control Citrus Juicer, 1, Black/Stainless

If you opt to remove the lemon rind and the pith before squeezing it, follow this process to make it as simple as possible:

  1. Cut off both ends of the lemon.
  2. Stand your lemon upright on the cutting board, resting it on one of the ends you just cut.
  3. Cut the peel and pith away from the inside of the lemon, moving the knife from top to bottom. Try to get as much of the skin and pith off as possible without damaging the inside of the lemon.
  4. Continue this process around the entire lemon until you have removed as much of the rind and pith as you can.

How to Reduce Lemon Pith Bitterness When Zesting

Zesting lemons using microplane
Zesting lemons using a zester or microplane tool.

If a recipe calls for lemon zest, you must use just the outermost part of the lemon peel (the yellow part). This part of the skin has a nice citrusy flavor and should not taste bitter at all. However, if you’re not careful when zesting the skin of a lemon, you could end up with pieces of the pith mixed in with your zest. If this mixing happens, you will end up with a bitter lemon taste.

The best way to ensure that you only remove the citrusy part of the lemon peel when zesting is to use a citrus zester or Microplane tool. Both of these tools provide you with fine, even pieces of lemon zest without cutting too deep and accidentally getting some of the pith as well.

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How to Reduce Lemon Pith Bitterness When Cooking

If you’re squeezing lemon juice into your recipe before or during cooking, make sure that you follow the steps I discussed above, instructing on how to gently squeeze out the juice to avoid it mixing with the pith.

However, if you’re using whole lemon slices in your recipe, you can try a few different steps to reduce the bitterness from the lemon pith entering your dish while cooking. These things include:

  • Use just the zest and the inside of the lemon in your recipe, and remove the pith.
  • Pre-boil the lemon peels, and then add them to your dish (boil until the water evaporates).
  • Taste your recipe frequently while cooking and remove the lemons right before they start to get bitter to avoid the bitterness growing too strong.

My preferred method is to use only the zest and the inside of the lemon (or just the inside of the lemon), as it is the easiest method and doesn’t require constantly tasting the dish to check for bitterness. I zest the lemon first and then cut off the rest of the rind using the process described above. 

Under Ripe Lemon’s Taste Bitter

Lemons are one of those fruits that do not continue to ripen after they’ve been harvested (unlike avocados or bananas). Therefore, ensuring they have already reached proper ripeness before harvesting from the tree is essential.

If your lemon is green and hard, it is not ready to be harvested and will have a bitter taste. If your lemon is primarily yellow, but still has a few spots of green on it, it could be ok but might not be quite ripe enough.

The lemon’s size, color, and firmness are some of the most important things to consider when determining proper ripeness. As mentioned, the color of the lemon needs to be yellow before it is ready to eat. Also as mentioned, lemons won’t ripen more once picked from the tree.

As far as size goes, a ripe lemon generally measures between 2 to 3 inches in length. Anything smaller than that size likely isn’t ripe yet.

Finally, gently squeeze the lemon between your fingers. A ripe lemon will feel firm but not extremely hard. Alternately, if it feels too soft between your fingers, it’s likely past its prime, affecting its taste as well.

Old Lemons Taste Bitter

Similar to using a lemon that is not ripe enough, a lemon that has passed its peak will also result in an unpleasant and bitter taste. As a lemon starts to go bad, it will also lose its citrusy taste and develop a more bitter flavor.

General indications that your lemon is starting to turn bad include the browning of the peel (or any discoloration), a mushy feeling, or a musty/fermented smell. If you’re unsure, you can try tasting a tiny bit of the lemon to see if it still has its citrusy taste. Of course, if you see any signs of rot or mold on the lemon, definitely throw it out.

Growing Conditions that Affect a Lemon’s Taste

Backyard Lemon Trees
Backyard lemon trees.

If you have a lemon tree in your backyard, as I do, you know it can provide you with an abundant harvest of this excellent fruit. However, if you discover that your beautiful tree provides you with bitter-tasting lemons, consider one of the following possibilities.

Bitter Rootstock Suckers

If you look at your lemon tree and notice a branch emerging on its trunk (below the graft union), you have a rootstock sucker. Rootsuckers will cause the fruit on your tree to taste terrible, even if it’s producing it in abundance.

Eventually, this little problem can overtake your whole tree if you don’t take care of it quickly enough. You should check your lemon tree often for rootstock suckers, and if you notice any, cut it off close to the tree. 

Lemon Tree Is Not Receiving Enough Water or Too Much Water

If your lemon tree is water-stressed, it could also produce unpleasant-tasting fruit, particularly bitter/dry fruit. This condition often especially proves true if the underwatering occurs during the final phase of fruit production.

On the other hand, overwatering the tree could also lead to poor-tasting lemons because the roots will sit in stagnant water and have trouble transferring the sugars and nutrients to the fruit as it grows. 

Related: Lemon Tree Dying? 7 Causes and Solutions!

Is It Dangerous to Eat Bitter Lemon Juice?

A small amount of bitter lemon juice will not cause you any harm, but you should refrain from eating large amounts of bitter-tasting lemon. As previously mentioned, lemon juice gets its bitterness from the glucoside hesperidins in the pith. Consuming too much may cause stomach upset, but usually the very bitter taste will have put most people off before it ever gets to this point.

How Can I Sweeten a Lemon?

Lemon tarts topped with whipped cream
Lemon Meringue Pies

The best way to sweeten a lemon that has a slightly bitter taste is to neutralize it with sweetness. Add sugar to the recipe or a bit of sea salt. Both additions work well at counteracting any lemon bitterness.

Additionally, if your lemon dessert has a bitter taste, try adding some whipped cream to the top to help sweeten the flavor.

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