"Anyhow its under gas atm i did get a chance to rack off 4 750ml bottles of un starsanned beer. What would youse do tip the keg out or wait and taste?"
Traily.
I feel your pain!!!!
I took a big slug of Irish coffee when I began to read about your dilemma and I laughed so hard (please forgive me) that I passed a mouthful of hot, alcohol laden coffee through my nose. It's hard to describe the buzz. I do not recommend for anyone to experiment with the process. But, since I was into it pretty deep, and being anal about anything related to alcohol I took some notes.
With a lung or two full of air and by measuring the volume of a mouthful of liquid and the distance that the volume of superheated, alcohol and triple caffeine fueled snot rocket travelled in the time period it took to expel all of the scalding hot fuel through my nasal passages, I was able to determine pressure drop through my nasal/sinus pipes. Also, I determined that the affects of superheated coffee blasted through nasal pipes makes brain freeze low key agony.
Check pH, it would be interesting to know what it is.
Have you ever tossed vinegar into baking soda? Foaming may have been due to a reaction of acid to a base chemical that should have precipitated early in the brewing procedure, but didn't, and ended up carried over. I could be entirely, wrong.
Place a pound of wet mash at 85F into an insulated vessel for three or so hours with the cap loose and foam will be flowing out of the container, mash temperature increases, aceto-bacteria. Pickle juice. Try it, the flavor is unique more like malt vinegar but not as sharp.
Here are a few suggestions for working with the beer.
If pH is extremely low and you pound down five gallons of it, it may be necessary to make an appointment with a dentist and with a Doc that works with stomach problems.
Use the beer to de-galvanize pipe.
Send a sample to Sandoz Pharmaceuticals.
Create a new style of Belgian Sour and call it Belgian Barnyard Farmhouse Saison Dark Sour and place it in a contest. It's blue ribbon material.
Use the beer straight from the keg to exterminate weeds by attaching a spray wand to the outlet spud.
If the beer/weed eradicator is an orange hue, it can be called Agent Orange Clone House Belgian.
I'm just kidding about all of the stuff. Sorry that it happened.
I left the cone in the fermenter full of sanitizer but, I only had a gallon of wort in the fermenter when I remembered.