"Unfiltered"

1. Filtered means the beer has gone through a fine filter to remove yeast and some residual proteins (trub, though trub is typically comprised of many things) that are left in finished beer. Many of craft brewers don't filter, they "leave behind" some of these proteins and much of the hop particulate matter after the boil by whirlpooling and after fermentation they use something like a brite tank (a large vessel that they cool causing trub to sink to the bottom) to clear the beer out. You can get pretty good results doing this.

2. Yes, pretty much for appearance. It eliminates "haze" and creates very "clear" beer which is desirable for some styles.

3. Plenty. Any style that calls for non-filtered, and pretty much anything else where appearance doesn't particularly matter (I don't know why you would waste time filtering a stout)

4. Wheat beers (hefes, wits), sours for sure. Anything bottle conditioned.

5. As a homebrewer I was always under the impression that filtering can leave something to be desired in mouthfeel so I would think stouts as well as the above styles would be best unfiltered. That said, I think there is legitimacy in leaving some DIPAs unfiltered when you're shooting for a particular mouthfeel (see: Heady Topper).

 

Thamajam did a great job answering the questions! Some additional thoughts:

1. I have nothing to really add here.
2. In addition to the appearance aspect the other potential benefit for commercial brewers is increased stability of the beer.
3. There was another thread where folks listed beers that they knew to be unfiltered:http://beeradvocate.com/community/threads/filtered-vs-unfiltered-craft-beer.76807/#post-1095246
4. Another beer style which is unfiltered is a Kellerbier. Southampton Keller Pils should be released shortly (it is a summer seasonal).
5. I personally believe that all beer styles are better unfiltered. I think there are flavor impacts (in a negative manner) to beer when it is filtered.

Cheers!

 

It depends what flavors your looking for. I agree there will be a different taste but whether it's better or worse will depend on who you ask.

 

...I wonder what an unfiltered Kristallweizen would taste like? Time to get "INNOVATIVE"! I think I'll call it Kellerkristallweizen.

 

Below is from the thread that I provided you a link to:

2. Beer taste stability
To stabilize beer taste both from non-biological such as haze and biological such as wild yeast, lactic acid bacteria and wort bacteria.
3. Beer foam stability
To ensure beer always have good foam.
5. Extend shelf life
The right practice beer treatment can extend shelf life up to 6 months.”

I want to emphasize the word “potential” in my previous statement of “potential benefit for commercial brewers is increased stability of the beer.” My homebrewed beers are unfiltered but I believe they are very stable (will last an extended time without staling) due to the fact they are bottle conditioned; a beer doesn’t have to be filtered to be stable.

Cheers!

 

Flavor stability. Some people believe that filtered beer tends to be more stable flavor wise over time. That is to say, unfiltered beer will fall off quicker or more unpredictably. I don't know how much actual research is out there to support this though.

 

“I wonder what an unfiltered Kristallweizen would taste like?” I know, I know: it will taste AWESOME! Just think Weihenstephaner Hefeweissbier!

Cheers!

 

Not innovative enough.

 

As with many aspects of beer appreciation there will be varying opinions on topics such as this. Below is an interesting quote involving the head-brewer of Sierra Nevada Brewery:

“When Steve Dressler of Sierra Nevada spoke at Hop Union’s Hop School he said they had stepped away from filtering that it tends to strip flavors.”

Cheers!