I know this post was from last year but just wanted to chime in.
about a year ago I made a 100% tallow bar, just to see what it would be like. And because I have a friend who's mom is allergic to almost everything, including most vegetables, so I thought it could work for her. I didn't put any fragrance in it.It ended up super hard. I mean you can't use that soap up! I've had one in my shower for months and it just won't go away!! It does create a nice fluffy lather though and cleans well. No complaints there. The thing I didn't like about it is that it did end up smelling kinda fatty. It might have just been me since I was aware of it. And it was a really light fatty scent, but it was there. I also made some really high tallow bars that I scented with EOs. After a year they really didn't have much smell left.
A few weeks ago I shredded what I had left of them up and put them in the crock pot with some goat milk and rebatched them. I also added a small amount of fresh soap batter because it was taking to long to melt down and I didn't like that it seemed really dry. I then added some lemongrass EO and some turmeric. The bars turned out amazing. Not fuffy or anything, a nice hard bar with a strong scent, nice color, and a great lather. I probably won't make the pure tallow or super high tallow soap again but what I ended up with a year later is really nice. Also, I use tallow at 40% in most of my recipes. I love it in soap. It just makes a great lather and a long lasting bar once cured. I've tried veggie oil recipes and they all just seem to go to mush or use up too quickly.
As far as rendering tallow is concerned. I have a few tips. I rarely do it anymore because I buy my tallow in bulk already processed. But here is how I do it and it's not as messy or time consuming...okay, maybe still time consuming but you can do other things while it's going. I personally use nut milk bags but you can also use old pantyhose legs. Put the fat into the bag (or panty hose), and cinch the bag or tie off the hose. put it in a large pan of boiling water, I would use about 1/4 to 1/3 of the total amount of fat. let it sit in there a while on a low boil and then once it starts getting soft, use a hand held potato masher to just mash it every now and again. I would sometimes let it low boil for an hour or two, adding more water as needed little by little, mashing it every now and then. when there's little left in the bag, you'll know it's done. All the fat seeps out and floats on top. You can try to strain the bag a little more with your hands if you want, but leave it sit out in a bowl or something to cool off a bit, then wear a few pair of gloves though cause it's still going to be hot. Or just skip that whole mess. I just never like to waste anything. lol. After the bag is out, I turn it up to get it to a good boil for a minute just to get it really hot so that all the fat will float on top. make sure you watch it because water and oil boiling can get pretty angry. Then turn it off, remove it from the heat, and let it cool for a bit. I then put mine in the fridge or freezer, gently without sloshing it around, with a towel laid down so not to crack the glass or anything. I also have an extra fridge outside that I store my tallow in and use for extra fridge space. if you are putting it in your daily fridge, you may want to let it cool a bit more and make lots of space around it because you don't want the heat affecting your food. Once it's good and cooled, I usually let it sit overnight in the fridge, you can cut the tallow in triangles out of the pan and rinse the solid pieces off under warm running water at the sink to get all the gunk off the bottom. years ago, I used to use rendered hamburger and bacon fat from when I was cooking when I first started making soap for my family. when I did that I often had to render it twice to get all the specks out. but if you have to do it a second time it's just a quick boil with more water and back in the fridge. no bag required. Anyway, I didn't intend to get into so much detail of the process, I just thought the nut milk bag/panty hose trick would be a useful tip, then thought that if someone reads this who never has done it before, they might need the full instruction.
ok. I'm going to bed now. I'm sleepy so I hope that my comment makes sense.