Iratherfly will have to answer about the pre-draining. It is my understanding that it is a bit more difficult to get a good set on store bought milk, but I have not used it and so cannot compare firsthand. How long did you wait before ladling? I am going to try pre-draining next time overnight. Do you have any pictures?
Sorry for another late reply here. If you purchased goat's milk in the store, it should be gently pasteurized (such as the expensive but good selections at Whole Foods, which are also organic and local, grass-fed in season). The problem is that most grocery stores carry national brands such as Meyenberg which is rather crappy. It's not clear where the milk comes from and what these goats eat or how they are treated. It is ultra pasteurized which sterilizes is completely from any naturally present lactic bacteria to make it last for weeks. These stores sell them in low volume, mainly for people who are lactose intolerant or for the occasional cook who wants to make goat pennacotta or something like that... This is simply not good enough for cheesemaking. HOWEVER, if you want to use it for cheesemaking, start by adding Calcium Chloride to stabilize it. Then add a generous amount of culture. (I would use a culture blend that can mimic the natural flavors of milk like MA4001 or Flora Danica. Remember that you need to build the bacteria from scratch here). Wait 6-12 hours before adding the rennet. then let it coagulate in a 70°F environment as long as it takes UNDISTURBED. Up to 48 hours if needed.How do you know when?
The milk should smell sour. Not rancid, but like yogurt. A ½" inch layer of whey floats on the top (use your clean finger to uncover it. Sometime a white mass floats to the surface of the whey and you think it is milk or curd but when you put your finger on the surface it clears to the side and you see that it is clear whey actually). Typically, the entire pot should be one curd mass. the curd should pull from the sides of the pot and it may display some cracks on top. This is the 4.5-4.7pH point that you want to drain it at. This curd still may be softer than regular milk curd and you will lose some yield. That's okay. (The ultra pasteurization may modify the structure or proteins and fat lipids so that's a part of it.) However, in these lactic / semi-lactic cheeses you can still make a good cheese out of it (unlike attempting a Camembert or Gouda with it).Pre Drain
I pre drain in a reuseable synthetic cheesecloth bag (better than colander and finer too). You want something very fine so that whey can take its time draining and doesn't stream out with all the minerals and solids too quickly. When the draining is slow, the whey and lactic acid continue to work on the cheese. Room temperature draining may begin to wake up the yeasts and fungi you are using for rind. I drain 6-12 hours, depends on what I want to do. If this is going to a mould with lots of holes and surface area I may drain only 2-4 hours.
This practice is good for French Loire Valley cheeses where the moulds only have a few weeping holes and are nearly at the size of the final cheese (so you need to fill them with curd amount that is not going to drain much further, otherwise you will get tiny cheese). Caprino method
An alternative method is the Italian one: Use high flow Caprino molds (I have hundreds in stock here by the way if anyone want). Ladle gently directly into these moulds. They are fine enough to capture the curd but have such high drain hole volume that they quickly drain the whey and compress the cheese to its final size. These moulds are usually tall and you ladle all the way up. the next morning they are ¼ full with nice solid cheese. It's less fussy (like anything Italian cuisine Vs. French...) but this cheese has a slightly different character.