Converting white bread recipe to whole wheat

65% vinegar would make for both an incredibly sour and sloppy dough, when added to the 68% water already employed.  ;-)

Some thoughts:

1. Depending on your preferences, drop either the sugar or the maple syrup.  There are sufficient quantities of either by themselves for an enriched dough.

2. Ditto for the butter and canola oil.

3. The vinegar doesn't bring much to the party in terms of the dough's or the finished bread's characteristics.  And, if you are cutting down on the sugars, it won't be needed to offset the sweetness.

4. You may want to experiment with increasing the hydration levels by adding water in 1% or 2% increments for successive bakes, until you have a bread that meets your desires.  As the bran content increases in tandem with an increased percentage of WW flour, the dough and the finished bread will feel drier at the same hydration levels than will an all-white flour bread.

5. I would definitely suggest an autolyse.  Mix all of the water, all of the WW flour, the cracked wheat soaker, and maybe half of the bread flour, then cover the bowl and walk away for half an hour.  That will give the bran time to absorb the water more completely, softening it and giving the dough a more uniform moisture level.  Then you can mix in the yeast, sugar, salt (just once!) and fat, followed by the balance of the bread flour.

Items 1-3 are a matter of taste, more than anything else, although both the sugars and the fats do have an effect on the texture of the bread.  Item 4 will, when you find the sweet spot for the flours you are using, yield a moister, softer, less crumbly crumb.  Item 5 will greatly reduce the amount of kneading you will have to do, since the gluten will already be developing during the autolyse.  It should also reduce the tendency of the finished bread to be crumbly at higher WW percentages.

One thing you didn't mention is how much water the soaker is contributing to the finished dough, so I can't make any estimates about how that will figure into the bread's characteristics.

I would suggest that you bake the as per the recipe is written (minus the second addition of salt and the massive quantity of vinegar) a few times until you have a handle on how it behaves.  Then start making changes, one at a time, so you can compare the results to the baseline you established with the original recipe.  Take notes along the way, and pictures, since they will help you with your comparisons.  I would start using an autolyse from the start, since that isn't a change to any of the ingredients, and since it will yield dividends immediately.  Once you have the bread at the point that you like, except that you want more WW content, then start increasing the WW content by, I don't know, maybe 5% increments.  You may find that you need to increase water, too.  

I hope some of this is helpful.

Paul

I concur with Paul

You don't say that you have actually used the former recipe only that you are thinking of adjusting it to suit  50% whole wheat.

If you have used the former recipe and like the way it performs both on the bench and in the mouth departments then by all means  experiment, but i would be inclined to make very small changes, using 50% whole wheat is a fairly big change and the addition of 30% cracked wheat is getting away from the original which you may or may not have tried already. Keep notes on what you use and how it performs, whether it achieves the results you are looking for. Try the whole wheat flour one time and try cracked whole wheat another.

I love making 50% wholewheat doughs but mine tend to be fairly simple and usually i like to soak my wholemeal in all the liquor (dark stout my favourite) for some complex flavours for 8 to 12 hours with a scant amount of yeast to get things started and then add all the rest of the ingredients, and a bulk ferment of about 3 hours. i have not been brave enough yet to attempt a full sour dough 50% whole wheat, i have used some of my sour dough starter in the preferment  but used dry yeast in the final make up and for a straight forward bulk fermentation. 

Going full s/d would mean big differences in the handling of the dough too. experimentation is great and it does suit individual tastes but 1 change at a time is the best way to have a proper comparison.

 regards Yozza