Basil does have a very pungent perfume & quite a strong taste especially when the leaves are shredded so I suspect you are simply getting the normal flavour of this herb if it's getting a little older when perhaps the flavour concentrates. As regards growing it - keep it in a sunny position and water well only when the soil starts to dry out. If it grows too leggy, snip off the tops to use in cooking. This pruning should encourage side shoots to grow out lower down and will help the plant to become more bushy. Incidentally, don't throw your upper talk prunings away. Put them into a glass of water and you will find that they grow roots very easily and you can simply pot them on in fresh compost and begin the cycle all over again. Once you've bought your original basil plant, if you adopt this practice, you'll never need to buy another one. You may find that as autumn turns to winter your plant starts being attacked by white fly which will rapidly weaken it. Spraying it with water may help reduce this. Keeping a flykiller solid block nearby will also discourage this pest.
If you get too much basil, use it to make pesto (a paste made with olive oil and pine nuts) which is excellent drizzled over salads as a dressing, or stirred into cooked pasta.