Colonial historic societies have some information on brewing in 1675. Both the Jefferson and Jamestown societies have investigated beer, wine and distillate making in those eras.
Jefferson was fond of a brewing book called "London & Country Brewer," published in the early 1700's and reflects some of the techniques from the era you're researching. Google has it online as part of the Guttenberg project.
At that time, the terms "Ale" and "Beer" were describing unhopped and hopped beverages, respectively. Ales, or Gruit, as is the modern term, would use boiling water to start the process, but not be further boiled. By 1720, the use of boiling would be commonplace, so you can bet that brewing at this time had some of it going on.
The making of ale or beer wasn't a kitchen process. The brewery usually had it's own stone foundation holding a copper metal insert, called a "Keeler" and yielded three gyles of about 20 gallons each. This would mean a single brewing day cold yield 3 weeks of beverages, though there was usually a brewing season and then they'd store much of it. The gyles were fermented separately according to records from elite households. They were presumably blended as needed depending on who was consuming and what time of year. Fermenting the whole wort together wouldn't be common until around 1720 with the rise in popularity of "Entire" or Porter, when London brewers regularly aged their beer at the brewery, instead of shipping it out young to be aged by publicans.
In the late 17th century, three were several variations to making hopped "Beer." The most familiar involved boiling just the wort with hops. However, I believe it was equally common to boil hops separately, then add it to sweet wort. Other variations included reboiling the same hops for each successive gyle.
The weaker gyles were typically served while very young, perhaps just a few days after primary fermentation. Yeast was not well understood (microbes were basically unknown), except that it could be reused from a good batch of beer and had been known as "God is Good." Mostly, it was thought of as an acid that split the sugars into spirits, but if not skimmed and left too long would split the spirits into vinegars. Periodiaclly, the yeast was rousted by stirring with either a paddle or oversized straw broom, which would naturally inoculate the next batch.
In addition to grain (not always barley malt), molasses, honey and other sugar sources were often used in the early colonial beers. Often these were made out of requirement, rather than for taste.