Just a quick refresher on what to expect from all Icarus Base soaps:
Goat's Milk - loaded with vitamins, minerals, fatty acids, amino acids, enzymes, and antioxidants. Honestly, the benefits of goat's milk in soap transcend the scope of this blog post - for further reading, check out this post by Bend Soap Co. The TL;DR is that it will moisturize your face in ways you never imagined (and is extremely synergistic with the additions below). The way I am using goat's milk prevents it from cooking, which prevents the breakdown of its beneficial properties (which, while adding a significant time investment, is worth it in the final product).
Lamb Tallow (not a replacement for bison tallow, just an addition) - Even more Vitamins (D, D2+3, and E). And even more selenium (thought to help prevent skin cancer, but - FDA - I am not saying that this is true).
Colloidal Oatmeal - The finest grind of oatmeal I could find, absolutely no graininess whatsoever. Oatmeal makes an excellent emollient (reduces water loss from the skin), anti-inflammatory, and even more antioxidants. In addition, it adds a very light exfoliation (you won't feel this exfoliation during lathering, but you will feel it after you shave when your skin feels - for lack of a better term - new).
Tussah Silk - Added as a lather texture enhancer. Get ready for soft, shiny, silky lather.
Tetrasodium EDTA - My water up here is about as hard as water gets, so I added some Tetradosium EDTA to provide some hard water resistance (though, as with all soaps, the softer your water is the better the soap will perform). Bonus points if you want to start blending distilled with a splash of spring and microwaving for optimal shave water - this holds true for any soap, not just Project Icarus.
Harder - I've received countless comments that my regular base is soft (which was by design). However, to mitigate those comments regarding Project Icarus, I have adjusted the KOH/NaOH ratio in order to produce a harder puck. The main side effect of this is shrinkage - Project Icarus does not adhere to the tubs in the same way that my standard bison base does, so it is possible that your puck will 'break free' from the tub. After a lather or two, small amounts of water will make their way under the puck, providing additional adhesive properties and should - going forward - keep the puck in place.
Avocado Oil and Castor Oil Ratio Tweaked - Adjusting this ratio (in addition to the hardness-increase noted above) provides a more 'normal' lathering experience (no more marshmallow-esque strings).
Thirsty - This soap is thirsty. And when I say 'thirsty,' I'm talking 'two days on Arrakis without a stillsuit thirsty.' The usable range of water is about as wide as the Marianas Trench is deep, so - by all means - experiment, experiment, experiment. Regardless of your water type/hardness, you should be able to get it dialed in into one of the best lather experiences you've had (and your face will thank you for it).
Potentially a bit on the gamey-side - Look. Goat's milk and lamb tallow (as well as bison tallow) are animal products that smell like animals. I have taken every precaution and used every technique at my disposal to prevent/mitigate this, but it is an inherent property of the ingredients used in the base. Once lidded and shipped (especially in the summer) it is going to smell like animal once open. The performance, lather quality, and post-shave feel make up for that gaminess, but don't be afraid to let it air out more. The more it airs out (as with my current bison base) the more the animal smells will fade.