Hops Utilization at Higher Elevations

[TomVA]

I live in Virginia's beautiful Blue Ridge Mountains at 2,600 feet elevation. As a result, water boils here at 207°F. Will this have any meaningful effect on hops utilization, i.e. should I be applying a factor to my IBU calculations?

TomVA

 

[mabrungard]

Yep, you should. This is the relationship I was able to derive from standard boiling point vs elevation data and hop isomerization rates determined by Malowicki and Shellhammer.

Elevation
Boiling Point
Multiplier on Sea-Level Hop Quantity

0 ft (0 m)
212 °F (100 °C)
1.00

1,000 ft (305 m)
210.1 °F (98.9 °C)
1.08

2,000 ft (610 m)
208.1 °F (97.8 °C)
1.16

5,000 ft (1,524 m)
202.4 °F (94.7 °C)
1.48

10,000 ft (3,048 m)
193.2 °F (89.6 °C)
2.30

Sorry for the crappy presentation since this forum doesn't provide proper text formatting capability.

 

[Smellyglove]

Yep, you should. This is the relationship I was able to derive from standard boiling point vs elevation data and hop isomerization rates determined by Malowicki and Shellhammer.

Elevation
Boiling Point
Multiplier on Sea-Level Hop Quantity

0 ft (0 m)
212 °F (100 °C)
1.00

1,000 ft (305 m)
210.1 °F (98.9 °C)
1.08

2,000 ft (610 m)
208.1 °F (97.8 °C)
1.16

5,000 ft (1,524 m)
202.4 °F (94.7 °C)
1.48

10,000 ft (3,048 m)
193.2 °F (89.6 °C)
2.30

Sorry for the crappy presentation since this forum doesn't provide proper text formatting capability.

Just to confirm. Your table means that at 2000ft you should use 1.16 times the hops comparing to 0 feet?

 

[TomVA]

Or put another way, if I have a beer that calculates to say 45 IBU at sea level, is my real IBU 37 (45/1.21 @ 2600 ft)?

TomVA

 

[mabrungard]

Just to confirm. Your table means that at 2000ft you should use 1.16 times the hops comparing to 0 feet?

That is correct.

 

[Nebraskan]

Or, you could do as I just did and boil hops in the wort in my pressure cooker. Takes only 15 minutes that way for the bittering addition.

 

[foam_top]

I wanted to share an article I bookmarked years ago but it seems the website is now subscription based. In any case, mabrungard's chart is very useful. I live in Denver and can confirm that ever since I started adjusting for my elevation it does make a noticeable difference.

 

[GPP33]

Interesting. I never thought of this. Also on the Colorado front range so according to that table I should be using 50% more.

This is the effect on iBUs, what about flavor and aroma additions? Are they unaffected since we’re not looking for isomerization?

 

[mabrungard]

Interesting. I never thought of this. Also on the Colorado front range so according to that table I should be using 50% more.

This is the effect on iBUs, what about flavor and aroma additions? Are they unaffected since we’re not looking for isomerization?

Those flavor and aroma additions are likely contributing to the overall bittering, but clearly not as much. You do raise a good question regarding the effect of boosting the total hop charge on the flavor and aroma. I don't know if the result would be excessive when correcting for elevation, but you could always concentrate on boosting the early bittering additions to achieve that elevation-adjusted IBU level while leaving the late addition quantities as-is.

By the way, these elevation-adjusted results were confirmed in results from a brewer in Leadville, CO. That is at 10,000 ft.

 

[Nebraskan]

My latest Munich Dunkel I used my pressure cooker for the bittering hops. Actually used the Instant Pot Pressure Cooker I use for roasts, ribs and such and put in about 3 cups of wort, then brought the SS pot to boiling temp on the kitchen range, put the SS pot into the Instant Pot pressure cooker and added the Hallertau Hops (in hop bag) and stirred, then set the lid, and time for 15 minutes on high pressure. Just tasted the beer this afternoon. Perfect! Just the right amount of bittering from the hops I was looking for.

With pressure cooker, you could use a large aluminum since it has been debunked about cooking beer in an aluminum pot, and get a pretty large bit of wort in there. Then, regardless of what your elevation is, just set the time and pressure and you get higher temps and faster cook time. Pressure is always constant this way, regardless of elevation.

 

[mabrungard]

Pressurized boiling will enhance the isomerization of alpha acids, but that higher heat can damage the wort through the production of thiobarbituric acid (TBA). That substance leads to quicker oxidation and staling of the finished beer. TBA production is a product of time and temperature, so I don't know if the higher temps are offset by the shorter heating time.

 

[Nebraskan]

..., so I don't know if the higher temps are offset by the shorter heating time.

They are. For one thing TBA is formed from boiling the wort, longer boil times means more TBA. Study was done on oxidation of fats like soybean oil and it's development of off flavors. However, I only used 3 cups of wort w/hops in the pressure cooker that, when finished the short 15 minute period, was returned to the main boil kettle (of 4.25 gallons) for an additional 20 minutes. I've lowered the time needed for overall boil to get the hops bittering from the isomerization, and in doing so, I have saved the main part of the wort from possible higher levels of TBA.

I kegged the Dunkel beer, I made using this shorter boil time/ pressure - return, on Saturday. Pressurized a small portion and refrigerated it and tasted that evening. Wonderful! Of all the Dunkels I have made this is by far the best and possibly the very BEST beer I have ever tasted. There is no estery aromas nor any off flavors to this beer. No DMS, or diacetyl either. Hops were added right before flame out and they come through in the finished beer.

Dunkel O.G. was 1.053 and at kegging (after fining 48 hours earlier) the F.G was 1.009. It fermented with no issues at all, very fast start up and fairly rapid fermentation. No sulfur smells or taste either.

I think the trick is to not use the whole batch for the pressurize boil, just enough to get your hops into solution and only then long enough to do that and no more. I think long high temp pressure cooking would, indeed, do some damages and cause off flavors. By using only 3 cups pressurized: 4.25 gallon total wort, my ratio of high pressure/temp was fairly small.

I live in SW Michigan, at elevation around 660 feet. Boiling starts at higher temps, not because of my lower elevation, but because of sugar in the wort. water boils at 212 F give or take depending on atmospheric pressure, but for practical use, 212 F (100C) at sea level. Water boils at lower temps at higher elevations, true. But, we are not dealing with water. We are dealing with wort that has around 12% + sugar in it, and that makes it boil at a higher temp, even at higher elevations. Same as my jelly making. When the juice boils and I add all that sugar it take a bit of time for the jelly to come back up to rolling boil, but when it does and I keep boiling, the temperature keeps rising even though it is boiling. It has to get to a certain temp for the jelly to set right. If it were not for the fact that we can exceed the temp of a boiling liquid, then people in Western Nebraska, where I was raised, could not ever make successful jelly.

 

[mabrungard]

I agree that pressure boiling that small amount of wort shouldn't significantly increase TBA. However, boiling the hops in that small wort volume would seem to create a situation where alpha acid and iso-alpha acid solubility would kick in. I'm curious if the intended bittering was actually imparted?

I'm also curious about the grist used in that Dunkel. Was there much pils malt? If it was predominately vienna and/or munich malts, then I can believe the acceptable DMS results in the resulting beer. But I'd be surprised that the short overall boil would be sufficient to convert the SMM and eject the DMS.

While we are dealing with wort that has sugars in it, boiling point elevation doesn't really kick in at the relatively dilute sugar concentrations that wort typically has. I studied that phenomena a few years ago and confirmed that even with very high gravity worts that we might see in brewing, the boiling point is NOT significantly elevated by that sugar content. As anyone who has boiled down wort to caramelize it can attest, the wort temperature doesn't really climb until the wort has lost significant water content...to the point that its noticably thicker.

 

[Nebraskan]

Here is the recipe online: https://www.brewersfriend.com/homebrew/recipe/view/581646/ yes, much Munich malts. I work in the lab at a winery and the ebulliometer has to be "referenced" every day if you are measuring alcohol, (EtOH) Reason: water boils at different temps, depending on the presence of high or low pressure at the moment. I have seen the thermometer read 100 C only a very few times. You have to have a base temp to put on the revolving reference before you put in the wine or cider (50 ml) to boil. I have seen it shift in a single day when the wind is blowing and the barometric pressure is changing. What the water boils at "at that moment" make a difference on what the wine (combination of EtOH, sugars, acids, water) boils at that given date. The thermometer is precise, calibrated, and tagged, so the only variable is what water boils at, and at what temp does the wine/cider boil at, then read the scale on the supplied wheel.

 

[mabrungard]

I don't dispute your lack of DMS since that recipe has no Pils content. That short boil method would likely have a substantially different outcome if the grist contained significant Pils malt content. The conversion of SMM and expulsion of DMS typically take longer than that.

 

[5SonsBrewing]

Yep, you should. This is the relationship I was able to derive from standard boiling point vs elevation data and hop isomerization rates determined by Malowicki and Shellhammer.

Elevation
Boiling Point
Multiplier on Sea-Level Hop Quantity

0 ft (0 m)
212 °F (100 °C)
1.00

1,000 ft (305 m)
210.1 °F (98.9 °C)
1.08

2,000 ft (610 m)
208.1 °F (97.8 °C)
1.16

5,000 ft (1,524 m)
202.4 °F (94.7 °C)
1.48

10,000 ft (3,048 m)
193.2 °F (89.6 °C)
2.30

@mabrungard Where can I find this formula to determine 6,050 ft of elevation? In the May/June 2019 edition of Zymurgy and your 'Advances in Worth Boiling' included a chart showing at 6,000 feet of elevation, the multiplier is 1.15. I must be reading the chart completely wrong! lol