Homemade yogurt didn't thicken up- anything I can do to salvage it?

Can I ask a stupid question? I’ve been making yogurt for years. I heat to 180 then cool to under 110. Add starter and process for 8 hours. I use whey from last batch for the starter. Always sets up well but remains a bit thin. I strain it for Greek style yogurt and the strained whey is clear. However, after straining, I’m not left with very much yogurt. A bit less than 2 quarts from a half gallon of 2% milk. Is there any way (or whey haha) to get the milk to produce more yogurt or is the fact that the whey is clear an indication that all available solids have cultured?

trying this as I type. It thickened but nothing like it did the first time I did this. I didn't put a heating pad under the crockpot on med low this time like I did the first time. My kitchen can get quite cold. Praying this works. I hate waste.

What if I reheat the yogurt and it get spoilt

I put my mixture into a jar, then into my bread machine, removing the blade, placing a plate over it, then put the jar on top. It is put onto a setting that is a long one for baking, no problems beautiful yogurt!

I have made yogurt for years. I take a 4 cup measuring cup and fill it with water and microwave it for 10 minutes (or to a boil). Leave in the microwave. Mix your yogurt up by following directions provided. Put in bowl and put in microwave along with hot water in measuring cup (in separate containers). I have had yogurt within two hours doing it this way.

Don't throw it out! 2 things you can do: freeze it in appropriately sized jars, and use it to stand in for the liquid in baking, in pancakes, bread, cake batter; etc.
Use as the liquid ingredient in smoothies, or popsicles.

Just add a bit of vinegar, put into bread machine, remove the kneading blade, put a small plate in place, place your jar or container on that, put the setting on low, 12 hours next morning great fresh new yogurt. I even strain the yogurt to get a thicker one, then can use as a filling in cakes. Enjoy!

Also if you have a homemade yogurt that you want to thicken up (Greek-Style) just pour the yogurt into a 2-3 layers of cheesecloth. Make a "purse" and then use the loose ends of the cheesecloth to tie it around your faucet. Let it hang overnight and in the morning you'll have super thick yogurt!

I was excited to prepare my yoghurt after reading online about the recipe and processes but I became nervous because my yoghurt didn't set at all after 7 hours of incubation. What could have caused that?

You may not be able to remake the bad yogurt, but I suggest you divide it into two parts and then leave one part in the fridge and add the other part to freshly heated milk then add half the amount of culture to it then let it set in the oven. This should work and you don't have to waste the milk-yogurt I make my yogurt all the time in my MEC pure clay pot the results are consistent each time. I learned how to make it from here : https://miriamsearthencookware.com/2013/04/11/how-to-make-thick-delicious-yogurt/

I used to make yogurt with goat's milk. At the time I was experienced with cow's milk (pastuerized) yogurt, so I used the same technique, and it wouldn't set. Maybe if Suzanne had been around (and the internet) I would have had her good advice, but what overcame the problem then was adding agar agar to it, and all was well. ...just in case!

Haha, Abbie! Anytime! Thursdays are raw milk delivery days- let me know if you want to try some of mine!

Friends and neighbors like yogurt leftovers, ahem, just FYI :-)

I reincubated for about 8 hours last night and it worked!! Super thick yogurt this morning! Thanks so much for your help!!

This is fantastic! Thank you so much! I'll try to reincubate and report back!

Found this great website, here is what she has to say about this:
If you wake up in the morning and your yogurt is still thin, the first thing to do is to put it back and wait a few more hours, since acid content, which is responsible for the thickening, will continue to increase with time. If after 12 hours your yogurt is still the consistency of milk, this means that it wasn’t kept warm enough during the incubation. Consider improving your incubation method or trying a different one.
Meanwhile, failed yogurt can be salvaged by re-heating it carefully over low heat back to 110 degrees and incubating it for the second time.