[quote]Ninety minutes produces about the maximum isomerization potential for alpha acids in wort according to work by Malawicki and Shellhammer. Beyond that time, the isomerized alpha acids are broken down to a slight degree and the bittering actually decreases. In terms of energy efficiency of converting alpha acids to iso-alpha acids, a boil time in the 60 minute range is better than 90 minutes.
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[quote]Longer boils tend to darken the wort and there are maillard reactions taking place producing more melanoidins that enhance the maltiness of the wort. Not to mention increased hop isomerization or enhanced hop bitterness. The longer boil also concentrates these flavors that are created during the boil. Driving off DMS is probably one of the biggest reasons to boil longer but these other attributes also come into play as well.
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Ok this is a bit over my head so if this don’t come out right what can I say. So can I assume if I employ a longer boil of 90 minuets to bring out the flavors of the malt and don’t start adding the hops until the last 60 minuets of the boil I can have the best of both worlds?
Yes, you can boil as long as you like. Some historical brews have even boiled overnight. But if you boil the hops too long you can get a veggie taste, so save them for the last 60-90 minutes. I don’t go over that length, but have never tested it.
[quote]Longer boils tend to darken the wort and there are maillard reactions taking place producing more melanoidins that enhance the maltiness of the wort. Not to mention increased hop isomerization or enhanced hop bitterness. The longer boil also concentrates these flavors that are created during the boil. Driving off DMS is probably one of the biggest reasons to boil longer but these other attributes also come into play as well.
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Ok this is a bit over my head so if this don’t come out right what can I say. So can I assume if I employ a longer boil of 90 minuets to bring out the flavors of the malt and don’t start adding the hops until the last 60 minuets of the boil I can have the best of both worlds?
I’ve heard/read the ‘no caramelization’ in the boil before and it all seems to make sense. But then what is happening when we do a ‘kettle caramelization’ of the first runnings a la Strong Scotch Ale? It definitely changes the flavor; a lot, and also changes the mouthfeel; a lot. It kind of tastes like caramel. So what happened?
blatz tasted my SSA in the Hurricane Blowoff. That was just base malt and a little roasted barley for color. All the ‘caramel’ flavor and a lot of the mouthfeel was from kettle ‘caramelization’.
Caramelization happens at elevated temps. This only happens when you have boiled off most of the water. It starts at 230F and must go higher for some of the larger sugar chains, > 300F.
So if you boil down first runnings in the kettle or a pan you can caramalize. If you boil all the wort at ~212F, you don’t caramelize. Are there elevated temps at the metal-liquid interface that can cause small amounts of caramelization? That I don’t know.
would you get some carmalization during a decoction ie if you basically fried the pulled part? and are any of the sugars carmalized during kilning at high temperatures?
Without doubt there are elevated temps at the metal-liquid interface. I have not been able to determine what these temps are/will be. Without a doubt the liquid wort/water will be at boiling temp, approx. 212F, in the kettle. Without doubt there is no caramelization there. There are issues commercially with removing heat with liquid from metal-liquid interfaces, and they have been in the news recently (the reactors in Japan). Different application but some of the same thermodynamic issues.
Scientifically it has never been proven that caramelization occurs in beer production. If it does it occurs on a micro level, and as I said there is no proof that this occurs.
As with making candy or boiling wort, once the water is minimized, carmelization will occur. I have boiled down a gallon of wort slowly and it got very dark. Of course it also very concentrated. The trick is to not rush it or it will burn. If that happens, it’s only fit for the trash.
Very good topic. ;D Going to have to do a test batch at an extended boil with a known recipe and see how it turns out compared to the normal way I make it.
If the temp was 230F or higher, only then would you have some caramelization. It would have to be pretty viscous. I’ve boiled down wort to a thick “molasses like” consistency but didn’t measure the temp. Next time I’ll have to remember to do that.
Returning somewhat to the original question about the benefits of a 90-minute boil, are there benefits to a longer boil?
I’ve recently done a series of beers with primarily pilsner malts, and the first two still came out with some DMS, despite a good rolling boil and pretty rapid cooling with immersion chiller. As I pondered this with a few people from my homebrew club, one or two of them suggested they typically boil even longer than 90 minutes, close to 2 hours, for pils-malt beers. Note that we are at 5,000 ft, and wort boils at 203, not 212 F. At least one person’s perspective was that at this lower temp, it takes longer to drive off the DMS precursors.
It is very likely to take longer at lower temps (higher altitude), but I have no experience with anything above 500ft so I couldn’t say how long you’ll need. 90 minutes is long enough for me at 500ft though.
How do you “scientifically prove” caramelization has occurred? Is there some lab technique involved?
I guess I’m less concerned with the explanation as I am with the outcome. If you boil your first runnings hard when making a Scotch ale, you get more caramel flavors. These aren’t the same flavors I get when I boil a decoction; those are a richer maltier flavor. Debate how they happen (the Maillard process isn’t well described, so good luck), but not that the results occur.
I just wouldn’t want people to start drawing the wrong conclusions, like “I heard you can’t get caramelization when boiling, so I can’t get caramel flavors that way.”
Good question Gordon. The answer is not straight forward and I believe caramelization is far too complex and a poorly understood process that produces hundreds of chemical products. The following are some of the reactions:
equilibration of anomeric and ring forms
sucrose inversion to fructose and glucose
condensation reactions
intramolecular bonding
isomerization of aldoses to ketoses
dehydration reactions
fragmentation reactions
unsaturated polymer formation.
So…now that we got that monkey off our backs we can now imagine how we get that caramel flavor in our beer. ;D