Bring 12 cups of water to a gentle simmer on the stove and dissolve the sugar and brown sugar in the hot water, stirring until it's completely dissolved. Allow the mixture to cool to room temperature.
Chop and seed the pears, leaving the skins on. Place them in your wide mouth fermentation vessel, either a single 2 gallon bucket or divided evenly across two one gallon wide mouth fermentation jars.
Add the remaining ingredients (except yeast), including sugar water, lemon juice, yeast nutrient and tannin powder. Stir to incorporate.
Dissolve the yeast packet in a small amount of room temperature water. Allow the yeast to rehydrate for 5 to 10 minutes, then add them into the pear/sugar/water mixture. Be sure to leave 2-3 inches of headspace to allow the mixture to bubble.
Cover the mixture with a towel to keep out flies/debris, or seal with a water lock if you're using wide-mouth fermenters that can accommodate that. Be sure to leave plenty of headspace at this stage, the pears can bubble up into the waterlock and make a big mess.
Allow the mixture to ferment in "primary fermentation" with the fruit in the mixture for 7 to 10 days.
Once fermentation starts to slow, use a sciphon to transfer just the liquid portion to a narrow neck fermenter for secondary. Leave the yeast sediment and fruit pulp behind.
Allow the mixture to ferment in secondary for at least 4 weeks, but up to 4 to 6 months.
Once fermentation is complete, taste the wine to test for sweetness (it'll taste rough at this point, but you're evaluating residual sugar). If you want a sweeter wine, make a simple syrup by dissolving a small amount of sugar in water. Add the simple syrup and allow the mixture to ferment for another 1 to 2 weeks before bottling.
To bottle, siphon the wine into wine bottles and seal with corks.
Allow the pear wine to bottle age for at least 2 weeks before drinking, but preferably 2 months or longer. The longer you wait, the better the wine will taste. Fruit wines taste a bit "rough" when young, but they'll mellow with time.
Notes
Wine Yeast
The alcohol tolerance of the wine yeast will determine the residual sugar in the wine (or sweetness when finished). Wine yeast can also contribute flavor to the finished wine. I'm using champagne yeast because it's a dependable fermenter with a neutral taste, but it has a high alcohol tolerance (around 18%).If you choose a yeast with lower alcohol tolerance, reduce the sugar by about 1/4 pound (or 1/2 cup), or expect a sweeter wine at the end. If you specifically want a sweeter wine, opt for yeast with a lower alcohol tolerance (13 to 15%). Lavin D47 is a good choice, as is Lavin QA43. See the article for a more in-depth discussion of wine yeasts.