Okay, now we're getting somewhere. Thanks for the additional info. Very helpful.
- 16.5 oz. sunflower oil
- 7 oz. coconut oil
- 5.5 oz. KOH
- 16.5 oz. distilled water
This will make a liquid soap that has zero superfat IF your KOH is 90% pure. If the KOH has a higher purity, there will be some excess alkali after saponification is done. Find out the purity of your KOH if possible to help troubleshoot this batch and to help you make decent recipes in the future with this KOH.
Another check you should probably make, if done with appropriate caution, is the zap test, because it will tell you if your soap has excess alkali or not. See:
https://www.soapmakingforum.com/threads/how-to-properly-safely-conduct-the-zap-tongue-test.63199/ I would zap test the liquidy part separate from the thicker part. If the soap doesn't zap, ignore the borax / citric acid thing. You don't need it.
If it does zap, yes, you will need to neutralize the soap. But let's get into that later if you need to go there. All I want to say at this point is do not dilute if you do need to neutralize. Also do NOT follow the instructions in your recipe. Come back here and ask for more advice about neutralizing.
If I was making this soap, the saponification would have been done after 30 minutes of cooking once the batter was at trace. An hour at the most. I can't speak about your situation because I don't know how you make soap, but I'd guess it's fairly safe to say the soap is done after 12 hours of cooking.
I would say the thick layer probably is not overcooked, but it may well be dried out instead due to the long period of heating -- water has evaporated out of this layer. There might also be some foam from mixing. Hard to say. But it's soap, that much is reasonably certain. I'd probably separate the firm part from the more liquid part and dilute them separately. You'll probably need to add a bit more water to dilute the thicker portion, but I think that is probably the solution to that particular problem.
When you do get into diluting, do NOT add all the water the recipe calls for. If you want to dilute, say, 500 grams of paste, start by adding 250 grams of distilled water. Get that mixed in. If it's too thick (and it probably will be) add half again that amount of water -- 125 grams -- and so on. Keep records so you know how much water is required to dilute a given amount of paste. That will make the next dilution of the remaining paste in that batch a little easier. Every batch of liquid soap is different due to differences in the fatty acid profile, the amount of water evaporation during the cook, etc.
And that brings me to another point -- did you use regular (high linoleic) sunflower oil or high oleic sunflower oil? If it's "suitable for frying", it's HO. I'd recommend using HO sunflower next time if you used regular sunflower this time. The amount of dilution water needed may vary depending on which fat you used.
Especially while you're learning, don't make large amounts of soap paste. And even when you're experienced at making liquid soap, bigger batches still aren't necessary unless you're supplying soap to an army. I normally make a batch using 300 grams of fat and that is enough to keep my family in liquid soap for months.
Recommended reading --
Irish Lass:
http://www.soapmakingforum.com/showthread.php?p=428988 see posts 8 and 9
and:
http://www.soapmakingforum.com/showthread.php?t=57974
Susie:
http://www.soapmakingforum.com/showthread.php?t=49852
Another good resource:
https://milesawayfarm.wordpress.com/2015/04/22/liquid-soapmaking-where-to-start/