Long Boil or Decoction Mash?

I was looking at a recipe for a Belgian Strong Dark Ale which called for a 3 HOUR BOIL! I use propane and have a pretty inefficient burner. To boil for that long, it would use over an entire propane tank. The OP's reasoning for this was to develop melanoidins and color.

Is a decoction mash an alternative to this long of a boil? From what I understand it will accomplish this. The original recipe is a single infusion mash, but if I were to change it, would the end result be at all similar?

Thanks everyone!

I did a single decoction for my Oktoberfest. Basically brought the mash from 152 up to 170 by adding a portion of the boiled wort. I can say it definitely increased the maltiness of this brew. It cleared really really well too.

I made a Scotch ale back in October that kettle carmelized over a gallon of wort down to a couple of pints. Same effect but more pronounced.

So I would say yes, the decoction seems like a viable alternative. 3 hours is just a long time to be sitting around.

I've heard that Melanoidin malt can help fake a decoction. Maybe aquarter to half a pound? I don't know, never actually used it:
http://www.northernbrewer.com/shop/weyermann-melanoidin.html

You could also take a gallon of the first runnings and boil them down separately on the stovetop.
Or you could just skip it and do a regular boil.
Or do the decoction. It's a lot of work, but I think it's fun. If you've never done it and decide to start off easy and only decoct once.

I like the idea of boiling down a certain amount of the wort. Is there any logic behind how much to boil down and how much you should shoot for as a final amount? This beer is expensive and I'd hate to have it ruined lol

A longer boil is an alternative to faking a decoction mash. It will increase the malt profile and color among other things. It will also virtually eliminate DMS from the wort so you won't have to deal with a major problem in that area

Just curious as to what the recipe is. Since it's a Belgian I was wondering if the bulk of it is Pilsner malt and if it is you should be doing a 90 minute boil anyways drive off DMS.

As far as boiling down the some wort separately in the past I have taken the first gallon of the first runnings and tossed it on the stove at full heat and just let it boil throughout while I'm adding hops and boiling everything else in my main kettle as usual. You get some nice kettle caramelization and some color. I usually do this for my malty Scottish ales.

Here is the recipe, it is mostly Belgian Pilsner (I ordered Belgian Pilsen malt assuming it is the same thing):
https://www.homebrewtalk.com/f73/rochefort-inspired-dark-strong-253190/

The mash is 90 minutes at 149. If I were to do a decoction, what would be suggested? Ive never done it before but have read about it. Or should I, for simplicity's sake, just boil down some wort?

I think any kettle carmelization is a side benefit of the long boil, not the reason for the long boil. The long boil is to get the volume down and the SG to the proper point. Long boils are very common for high ABV beers. With all that grain it takes a lot of sparge water to get all of the sugars out. Hence the large volume and the need for a long boil time.

One way to save on boil time is to double mash. Basically you take half the grain and mash as normal (a bit thick), drain that off, do a very small sparge, and then use that wort to mash in the second half of the grain. After conversion then sparge as normal. With this method you can get a wort with a higher pre-boil SG. This is in a smaller volume too so it requires less boiling.

I did the above once quite successfully for a 13% ABV beer. I only had my normal 7 gal. after the second mash so it was just a 90 min boil. I used pilsner malt so I targeted for a 90 min boil to remove DMS precursors - if I had used pale malt, I would have just gone 60 min boil (and used 0.5 gal less for the first mash in)


Now if you are just looking for the flavors and not the higher ABV, then try the melanoidin, or boil down the first gal of wort by half, to get some carmelization, and then add the rest of the wort and proceed with the boil

This recipe isn't as big of a beer that would need a 3 hour boil to condense the wort. It is 1.078 and that is with 1.5 lbs of sugar added. The OP even said the reasoning was for color and flavor. I will just boil down 1 gallon of 1st runnings to recreate that.

+1 to pjj2ba's post.

You will get more malliard reactions in a shorter period of time if the wort is concentrated (but you'll also get carmelization reactions). From an energy efficiency perspective, I would take the first thick syrupy runnings from the mash and put them into a pan on the oven and start cooking them down as you finish running off the mash and sparging. You'll get a load of darkening and malliard reactions in that amount of time and you'll certainly save gas. Anything greater than a 90 minute boil is wasteful, IMHO; even 90 minutes should get rid of DMS in the most sulfury of lager malts.

Malliard malt is another alternative. The verdict is out on whether this is REALLY a replacement for decoction mashing or not, though; many would argue that there's much more complicated chemistry happening in a boiling mash than just malliard reactions. -Watch your sugar temps with a sugar thermometer so it doesn't harden into rock candy, though...