Full boil or actual temperature?

[mahilly]

I have seen many threads touting the importance of a full boil. But is it the boil, or the actual boiling temperature that is most important? Some brewers live at higher altitudes so their full boil is going to be at a lower temperature than others.

Thinking 'outside-the-box' here (hate that expression): has anyone tried using a pressure cooker to up the temperature of their boil? How high is too high regarding temperature?

 

[orangeandblue302]

In my experience, and from what I have learned in my short, but successful, history I believe that a rolling boil is for sanitary purposes. A boil is sustained to make sure every possible measure is taken until its totally out of your hands.

 

[alpo]

I don't have anything to add other than I would guess a pressure cooker big enough for a full, or even partial boil, would be like a thousand dollars.

 

[A4J]

A rolling boil achieves several things:
1. Extracts, isomerizes and dissolves the hop α-acids
2. Stops enzymatic activity ( if they would not be destroyed, they would continue to work during fermentation)
3. Kills bacteria, fungi, and wild yeast
4. Coagulates undesired proteins and polyphenols in the hot break
5. Evaporates undesirable harsh hop oils, sulfur compounds, ketones, and esters.
6. Promotes the formation of melanoidins and caramelizes some of the wort sugars (although this is not desirable in all styles)
7. Evaporates water vapor, condensing the wort to the proper volume and gravity (this is not a primary reason, it's a side effect of the process).

Doing a full boil also helps with hops utilization and minimizes scorching of the malt extract.

 

[mahilly]

I don't have anything to add other than I would guess a pressure cooker big enough for a full, or even partial boil, would be like a thousand dollars.

probably true. I'm not suggesting a pressure cooker makes logistical (or financial) sense. Just wondering if, in theory, increasing the temperature above 212F might improve the final product.

 

[A4J]

Pressure cookers have been used in the brewing process. Do a search on steam infusion mash or check out this thread.

 

[spage]

Unless you live on a space station, the boil temps should be sufficient for sanitization. The main purposes of a good rolling boil are:

1. Sanitize the wort and kill undesirable bugs
2. Evaporate sulfur, ketones, and other nasties
3. Utilize the hop alpha-acids to make your tasty bittering units

Even if you live a mile up, you're only talking about a 10% reduction in boil temp. Try increasing your boil time by 10% and see how it turns out.

Oh yeah, RDWHAHB. Cheers,

 

[Rudeboy]

Boiling is also required to boil off the DMS. So the pressure cooker wouldn't work as it's covered. Realize the pressure cooker was just a theory, but the take away is not to ever cover your boil. It's important to let the steam evaporate away. If it's covered such things as DMS would just condense on the lid and fall back in.


Rudeboy