If you are looking to enhance complexity in your wines, try some oak chips or granules. These oak chips/granules are exactly what professional wineries use to make their wines taste like wines that are aged in expensive oak barrels.
These premium granules (fine chips) are available in French or Hungarian oak. The french oak is more subtle and [arguably] complex than its American counterpart. The Hungarian Oak has a flavour profile somewhere between the French and the American. These oak granules will also darken the colour of your wine & may speed up the maturation process..
Also suitable for making your own spirits and other culinary applications eg smoking.
Use 5 to 10g per 5 litres / 1 gallon of your homemade wine. You can always add more oak; but you can’t remove it, so experiment with less until you have established your preferred dosage.
Options for use (or as per your recipe):
1/ Add to the primary fermentation at the same time as your fruit.
2/ Soak in boiling water, strain & add strained water to your primary fermentation (for a subtle flavour).
3/ "Rack" (siphon your wine off the sediment) your wine for aging. Soak the oak chips in potassium metabisulphite for 20 minutes. Strain. Add the oak chips during aging (after racking). Taste your homemade wine regularly. Rack off when the desired level of oaking is achieved.
4/ Rack your wine for aging. Soak the oak chips in boiling water for 5+ minutes. Add the water & the oak chips to the carboy. Taste your homemade wine regularly. Rack off when the desired level of oaking is achieved.