[bluedog]

Is lactose truly unfermentable? How many ppg would be in a pound of lactose? I am thought about this as I was backsweetening a mead. Instead of adding potassium sorbate first and then honey, couldn't I sweeten with lactose and not have to worry about refermentation?

[tschmidlin]

Unfermentable by yeast, yes, and you could use it to sweeten your mead instead of honey without using sorbate.  It is not especially sweet though, only about 1/5 as sweet as table sugar.  So you'll need to add a lot more lactose to get the same sweetness as with honey, which will add a lot more to the body.

[bluedog]

Sounds like sorbate and honey then...

[tschmidlin]

Well yeah, except you need to add 5 times as much lactose to get the same level of back sweetening as with honey.  That'll have roughly 5 times as much affect on the body of the beer.  So if you want to add body but not as much sweetness as you get from honey, then maybe lactose is a good call.

[corkybstewart]

I turned a crappy batch of pale ale into 4 gallons of excellent malt vinegar.  Then I made a batch of cider just for vinegar-crabmeat salad with homemade cider vinegar was amazing.  Right now I've got another batch of malt vinegar fermenting from a very lightly hopped pale ale.
On a side note being completely ignorant about the dangers of acetobacter I made the cider vinegar in one of my corny kegs.  That was 10 years ago, there's no telling how many batches of beer I've run through that particular keg over the years, and I've never had an infected keg of beer.

[euge]

Is lactose truly unfermentable? How many ppg would be in a pound of lactose? I am thought about this as I was backsweetening a mead. Instead of adding potassium sorbate first and then honey, couldn't I sweeten with lactose and not have to worry about refermentation?

I've never had it in a beer or the like that I know of, but it seems to be a good choice for brewers wanting to sweeten their beers without additional fermentation.

A word of caution though: I've had "sugar-free" candy made with lactose and it gave me gas real bad. I mean in an unnatural painful bloated fashion. Saccharomyces Cerevisiae can't handle it and our own intestinal flora appears to have a rough time too... This has kept me from using it in my beer.

[tschmidlin]

I've never had it in a beer or the like that I know of, but it seems to be a good choice for brewers wanting to sweeten their beers without additional fermentation.

A word of caution though: I've had "sugar-free" candy made with lactose [ . . . ]

Some people are lactose intolerant

It's frequently used in milk stouts.  Left Hand makes one, Widmer's Snow Plow, Mackeson XXX, etc.  Good beers.

[monomer77]

I've used lactose to back sweeten. It kinda works. I've used 1 # in 5 gallons. It doesnt sweeten it up much, flavor wise.

I've used it at the beginning of fermentation to cut the super dry character of cider or a mead. Works pretty well to create a semi-sweet mead flaovr. That way instead of fermenting to 1.000 or less it'll land at 1.004-1.006. which is a big difference when drinking/tasting wine/mead.

I've asked the question before and been told that lacotse is not fermentale at all, 0 percent. (enter nerd who will tell me it's 0.0007854% fermentable.)