Bitter Basil

I grow and use a lot of basil, and maintenance practices necessary for great flavor don’t always happen when they should.

Basil is one of those herbs that can be quite sensitive to weather, growing conditions, harvest practices and storing conditions. When I only grow one plant I am using it faster than it produces so many of these issues never even present themselves. But since I never want to risk running out or heaven forbid, plant failure, I often grow three or four plants. Then I have to pay attention so none of them turn bitter, leaving me with nothing for pesto!

Many of us commonly grow the sweet Italian Basil tor our sauces and pesto, which of course are best when your basil is sweet and aromatic. Of course your basil should be growing in well drained organically rich soil with at lease 6 hours of sun for starters. Naturally we water our basil regularly and give it occasional organic fertilizer. But there are several things you can do to maintain sweet robust flavor in your basil. Nothing difficult or time consuming, but little tweeks in habits can make a huge flavor difference.

PRUNE

The single most important thing you can do to keep your basil sweet is prevent it from flowering. It completely ruins the basil. The flowers lead to seed production, so this is the last act of any annual it its’ life cycle. It is preparing to die and all energy will go to developing the flowers and seeds. Not only will leaf growth halt, but more importantly, the production of the natural oils that make the leaves sweet will drop rapidly.

The oil content is highest and producing the best flavor right before flowering begins. So if you are harvesting frequently the basil should be in a constant state of readying for flowers. If you are not harvesting quickly enough (because like me, you have too many plants that have grown robustly bushy!) you should be pruning off the tips. Watch for a very tight cluster of what looks like many tiny basil leaves at the tips. That branch is about to flower. Pinch that tip off right away.

If your plants have gotten so well branched that you cannot use it fast enough, you might want to prune the plant quite severely. This is something you should also do before you go on vacation to prevent flowering in your absence. Snip the plant back to half, or even down to the second set of leaves. Cut just above a pair of leaves. Fresh, sweet, new foliage will be produced. You can do this as often as monthly, at least for about a year when it will just start to give up its’ mission of propagating and die. It is an annual after all. You can also try very severe pruning if flowering got away from you but the basil has not begun seed production yet. Typically the fresh foliage will again be sweet as the plant decides to try the whole process again. If seed production has begun, the plant has already become woody, bitter and begun to die.

HARVEST TIMING

This one is hard for many of us who work every day. Get home from work, start a recipe, go out and snip some nice fresh basil. Unfortunately that is not how we get the best flavor from our basil. The wind and heat of the day can dissipate the essential oils and result in dull flavor or even sour bitter taste. Cutting your basil with the early morning dew on it can also reduce essential oils. Ideally, harvest in the morning when the plants are dry and winds are calm. Remember that the flavor begins to change as soon as you cut the leaves, so try to only harvest what you need right away.

STORAGE

Yes I did just say cut only what you need, but unfortunately we cannot always harvest at the perfect time each day. So do keep your harvest to a minimum and store it properly. Basil is very sensitive to chilling temperatures so we cannot store it in the crisper like many herbs. It prefers temps over 50 degrees, so store your basil like fresh flowers, with the stem in water in a small vase or narrow cup. To keep the sweet flavor even better, cover the cutting with clear plastic. Your cutting may keep fairly well for a couple of weeks.

VARIETY

If you have ventured into some new varieties, just don’t expect them to have the sweet flavor of Mediterranean or Italian Basil. Some basil may seem bitter in comparison but in reality may just have a sharp or spicy flavor that you are not used to. You just might even want to try one with cinnamon or lemony flavors.

There are a couple other things that can alter the flavor of your basil. Changing the location or growing conditions may not necessarily turn basil bitter, but may certainly alter the flavor and aroma. Heat in particular, even from your food processor blades might give basil a bitter taste. Likewise, heat in your sauce, so add the basil toward the end of your cooking process to retain basil’s sweet delicate flavor and aroma.

CAN I SALVAGE BITTER BASIL?

Once basil has gone bitter it is not quite possible to salvage it for a delicious pesto, but there are things you can do to make some use of bitter basil. It will never be repaired to a delicate sweet flavor but perhaps save it from the compost bin at least.

If your basil has started to produce a few flowers unnoticed, immediately pinch the flowers off and hopefully the flavor will not be affected. Or hard prune the plant to regenerate If your basil has several flowers. If several flowers are maturing toward seed development, the plant will not be able to restore itself to producing sweet basil. In that case, harvest everything quickly to prevent further loss of flavor and added bitterness.

Blanch it and freeze it. The blanching will reduce bitterness but then must be used immediately or just freeze it for winter use. Blanched and frozen basil will be perfectly acceptable tossed into sauces or soups.

Add a bit of sugar, just as you do to your homemade tomato sauce to sweeten up tomatoes.

Dilute it, or basically dilute the bitter taste by adding it in small amounts to sweet basil. Or use small amounts of bitter basil with spinach or chard, especially if using greens in a sautee.

If seed production is well underway, you might as well let the process finish and save seeds for next season. Let the seed heads get brown and dry, snip them off and crumble onto a white paper or plate to sort. The seeds will be the hard dark somewhat oval shaped bits. Store the seeds in an airtight container in a dry dark place.

Here’s to a season of plentiful sweet basil!