"You could measure 10ml of this, 20ml of that, taste it and see what you thought," said Mr Meredith.
British wine experts have imparted advice on how to change the body and flavour of a wine by tweaking the concentrations of red grapes.
Victoria Moore, the Daily Telegraph wine correspondent, said she often added shiraz to one of her favourite bottles, which was 100 per cent grenache. "It just lifts the flavour," she said.
"If you have a really expensive bottle of wine it wouldn't be worth taking the risk ... But why not start messing around with cheaper supermarket wines? It will give people a much better appreciation and understanding of what they are tasting."
Spanish winemaker Campo Viejo has been holding wine blending courses in London as part of the annual Streets of Spain festival.
Mr Meredith said that wine blending was a centuries-old practice especially popular in the Bordeaux region of France but he was yet to hear of people mixing their supermarket-bought bottles together in the kitchen.
"But there is no reason people shouldn't do it at home."
First-time blenders should start by mixing wines that are similar in character.
For example, blend heavy reds with other heavy reds, or try a little peach wine with reisling.
Winemaker Robert Vicente suggests starting with grapes that are already known to work - such as cabernet, merlot and shiraz - and playing with the concentrations to find the perfect blend.
"It is easier to understand what each wine adds to the blend when flavours are simple but clear."
- Staff reporter, Daily Telegraph
