Well, the water spray was at the top of my list :-)

I'd try a prepared insecticidal soap (Safer, Garden Safe are common brands). All of these are approved for organic use and tend to have much better efficacy than homemade soap solutions. Any kind of insecticidal soap can produce the phytotoxic effects (leaf burning) on certain plants. Try spraying at dusk to minimize that effect. Or introduce lady beetles (ladybugs) or other predatory insects (green lacewings, praying mantis) for a biocontrol.

Your soap to water ratio is way too strong. You'd be far better off with a commercial insecticidal soap, as GG suggests. Such products are also approved for organic growers and producers.

A sharp spray of water, nothing more needed, will knock any aphids on the plant off and then they get lost. Since aphids are most attracted to plants with lush green growth the soil the vine is growing in may have too much Nitrogen, and that may be the attractant.
An insecticidal soap solution needs only be 1 teaspoon of the soap mixed into 1 quart of water. When you spray may also affect the plants since any soap residue could cause the sunburn you are seeing. Spray that IS mixture before 6:00 am or after 5:00 pm.

Are ants protecting your aphids? If not, ladybird larvae would gobble them up. Which reminds me of the precept that organic isn't so much about substitutes but rather a whole differeent system of gardening. Regards, Peter B.

What rhizo said. I use 1 tbsp to a quart bottle for really heavy infestations of aphids, at dawn or dusk-ish. A dash of cayenne & a clove of garlic is a cheap, decent repellent too.

Dan

If the water does not work, try cinnamon or hot pepper oil.

Someone has told me to try 1 onion, 3 cloves of garlic.
Crush the bulbs or use a food processor, then soak in a gallon of water over night. Strain 1 cup, to remove pulp & put in a hand sprayer then fill with water, shake to mix & spray.