When we visited the Nantucket Wine Festival, we talked at length with the Sam Adams Beer rep about their plans for a low carb beer.
The rep explained that Sam Adams maintains a testing facility in Jamaica Plans, Massachusetts. The brewers often play with various combinations, to determine new blends and opportunities. They have worked on finding a low carb beer combination, but up until now none of the low carb formulas have given a rich enough taste to warrant the Sam Adams label.
The Sam Adams Light, which took a lot of work to complete, has 9.2g of carbs - not very low at all compared to the many 2g and under beers now on the market. Note that in the beer market, Light has traditionally meant "low calorie" - NOT "low carb".
However, the rep felt that those 9.2g are not all fully digestible, and said that Sam Adams would work in the future to explain this better in their site and material.
He discussed how light beers in general have become a huge force in the market - something that few beer makers would have thought possible a short while ago. It used to be assumed that beer drinkers were not a group that cared about weight - they drank because they liked the flavor of beer. But nowadays Bud Light outsells Budweiser, and this is true for many other brands as well. It turns out that beer drinkers DO want to avoid that "beer gut" and are willing to drink a lighter beer in order to stay healthy.
The rep explained that Sam Adams brewers HATE it when people put the beer in frosted mugs, or add limes or lemons to it. They go through incredible amount of work to make the beer just right - and the addition of ice or fruit makes great changes to the flavors.
The rep was not a low carber, and at one point said that Bud Light had it right when they claimed that "all light beers are low in carb". We laughed and said that this was completely false. Just look at (ahem) Sam Adams Light which is 9.7g a bottle! That is over 4 times the carbs in other light beers. To a low carb dieter, this is a HUGE difference.
NOTE: As of August 2007, the formula they are using is 119 calories and 9.6g of carbs.
Low Carb Beer Chart
Lisa Shea's Library of Low Carb Books