Thoughts on boil-off rate?

[J_Flint]

I was perusing a thread about having consistently produced watery beer and stumbled across a paragraph posted by Martin Brungard regarding how an excessive boil off rate can negatively affect beer quality.


"Well here's another myth that will die. Excessive and prolonged boiling CAN AND DOES actually damage wort. Back in the day, pro brewers did boil off with long and hard boils that evaporated 15 or more percent of the original wort volume. Then they had the realization in the 70's, that energy efficiency was actually a good thing (oil embargo) and there was a flurry of activity in investigating wort boiling and what its effects were. They found out about what it takes to deal with DMS and other volatiles in wort. They also devised better kettles that significantly reduce the heat stress on wort and the amount of evaporation. Now, modern breweries are typically evaporating 4 to 10 percent of the original volume and still producing the DMS reduction they need for good beer. I'm not going to steal the thunder of my upcoming HomebrewCon presentation, but I've spent over a year of intensive study on this subject and conference attendees and AHA members will learn more about this subject and why they shouldn't be abusing their wort that way.

One effect of excessive boiling that may align with this thread's subject is that you can reduce the wort's Coagulable Nitrogen content too low and that can reduce head retention and possibly some body."

My system boils off about 1.5g per hour, and I have produced some beers that were a little watery, moreso than I'd like. Anybody have thoughts on this subject?

 

[Robert65]

I used to over boil like most. I started becoming aware of, and trying to apply, the information in the professional literature a number of years ago, and this was one of the greatest improvements I've ever made. The difference in fresh, lingering malt flavor, body and foam qualities, delayed staling, and more can be night and day. I do a low intensity, 60 minute boil, with the lid almost completely on (just a crack to expel some steam,) and target 4-6% total evaporation, usually hit 6-7%. One trick I've discovered is heating the kettle asymmetrically, with the flame (yeah I use old fashioned fire) off center. This allows for excellent circulation of the wort, to facilitate protein coagulation and bringing undesirable volatiles to the surface for expulsion, at a mere simmer.

Martin adapted his HBC presentation into an article in the May/June 2019 Zymurgy. It's an introduction to the subject that's well worth a read.

 

[J_Flint]

I used to over boil like most. I started becoming aware of, and trying to apply, the information in the professional literature a number of years ago, and this was one of the greatest improvements I've ever made. The difference in fresh, lingering malt flavor, body and foam qualities, delayed staling, and more can be night and day. I do a low intensity, 60 minute boil, with the lid almost completely on (just a crack to expel some steam,) and target 4-6% total evaporation, usually hit 6-7%. One trick I've discovered is heating the kettle asymmetrically, with the flame (yeah I use old fashioned fire) off center. This allows for excellent circulation of the wort, to facilitate protein coagulation and bringing undesirable volatiles to the surface for expulsion, at a mere simmer.

Martin adapted his HBC presentation into an article in the May/June 2019 Zymurgy. It's an introduction to the subject that's well worth a read.

So if I was shooting for ending kettle volume of 6gal, you would have me boil off less than .5gal? That seems so...strange. But you say you have noticed a perceptible quality increase in your finished beers?

Yeah I use fire too...is that really considered old fashioned these days?. Lol. I love my fossil fuels. Can't stand those electric cars either. Hah!

My normal procedure is to mash 1.25qt/lb in my mash tun, and I usually collect around 3-3.5gal. of wort. Then I employ a single batch sparge and collect another 4-4.5g. Boiling for 60min usually lose about 1.5g.

My last brew was a brown porter but I used BIAB method with similar boil volume. The beer has a good forefrontal flavor, but the finish is weak, watery, and thin tasting.

 

[Robert65]

Over boiling can thin it out because it keeps on breaking down proteins. You want to coagulate and precipitate the haze forming ones, but that doesn't take much. Yeah, after a couple of decades of mad boiling, it's a major mental adjustment. But the results are worth it. Even that initial malt flavor can be improved: a little heat will start forming simple melanoidins -- yum. As you progress, more complex forms develop, which are increasingly unpleasant.

 

[J_Flint]

Over boiling can thin it out because it keeps on breaking down proteins. You want to coagulate and precipitate the haze forming ones, but that doesn't take much. Yeah, after a couple of decades of mad boiling, it's a major mental adjustment. But the results are worth it. Even that initial malt flavor can be improved: a little heat will start forming simple melanoidins -- yum. As you progress, more complex forms develop, which are increasingly unpleasant.

So you would say the general figure of 1-1.5g/hr boil-off is "mad boiling," or at least over boiling?

I'm also worried about efficiency because I usually am sparging with more water than I mash with and I feel like this contributes to good extraction efficiency.

 

[Robert65]

Well, efficiency and quality don't always meet. You can play around with mash and sparge ratios to hit closer to your OG the boil, even if it means using a little more malt.

 

[J_Flint]

Well, efficiency and quality don't always meet. You can play around with mash and sparge ratios to hit closer to your OG the boil, even if it means using a little more malt.

I suppose I agree. I'm a stickler to myself for efficiency, but in the end the difference between beer and good beer would be worth it. Do you have an opinion on mash thickness and it's impact on certain characteristics? I've been trying to perfect my English Bitter lately and have read the they are made with a very thick mash traditionally..

 

[Genuine]

This is super interesting to me. I’ve been brewing on my electric system now for the past couple of years and I usually turn my controller down to 50-60% power on my 5500w element and I generally shoot for a gallon boil off in the hour long boil, which in my system is 14.3% . I’ve been wondering if boiling for a Lower boil off rate would be useful somehow (and save energy).

 

[Spartan1979]

I used to boil off 1.5 gallons per hour when I was using propane out in the garage. With my electric system I'm only boiling off 0.5 gallons per hour. I'm using a 3750 watt Boilcoil at 33-40% with a steam condenser. I certainly haven't noticed any negatives from this. I'm not sure if there's been any positives.

 

[Carolina_Matt]

I always did a low boil-off when I used propane, mainly because I was so fearful of boil-overs. When I moved to the 120v digiboil, I just use it at max power (1500W) and I get a good (but not vigorous) rolling boil with 0.8 gallons/hour boil-off. That seems to work very well for me.

 

[RPh_Guy]

For "watery" beer, the first thing you should investigate is water chemistry. You possibly need to increase your chloride and/or sodium.

You may also consider step mashing and reducing your carbonation if it's too high.

 

[LittleRiver]

So you would say the general figure of 1-1.5g/hr boil-off is "mad boiling," or at least over boiling?...

Not necessarily, dependent on your kettle geometry.

If you have a large kettle with a wide opening, say a Bayou Classic 15gal, you can have a boil off rate of ~1.2gph with a very gentle boil.

 

[RPh_Guy]

Not necessarily, dependent on your kettle geometry.

If you have a large kettle with a wide opening, say a Bayou Classic 15gal, you can have a boil off rate of ~1.2gph with a very gentle boil.

Partly/mostly covering the kettle will help reduce boil-off rate in order to reduce thermal stress.

 

[homebrewer_99]

.5 gal per 30 minutes for me.

 

[J_Flint]

I guess I was mostly wondering what y'all thought about the effects of boil-off rate and what it does to the finished beer. It seems that some people believe even what is considered an average rate (1-1.5gph) can have detrimental effects on finished beer such as poor head retention, mouthfeel, and shelf stability.

 

[J_Flint]

I guess I was mostly wondering what y'all thought about the effects of boil-off rate and what it does to the finished beer. It seems that some people believe even what is considered an average rate (1-1.5gph) can have detrimental effects on finished beer such as poor head retention, mouthfeel, and shelf stability.

 

[RPh_Guy]

http://www.lowoxygenbrewing.com/uncategorized/low-oxygen-boiling/

 

[J_Flint]

Edit- sorry double post

 

[J_Flint]

http://www.lowoxygenbrewing.com/uncategorized/low-oxygen-boiling/

Cool read! Thanks. So I should be targeting <.5gph boil off to take advantage of the benefits mentioned here? Is boiling for 60min. Still advisable for good hop utilization, granted I keep the boil to a well controlled simmer?

 

[RPh_Guy]

evaporating 4 to 10 percent of the original volume

target 4-6% total evaporation

Yup, same stuff already mentioned above

Hop utilization isn't an issue regarding boil vigor.

 

[Cavpilot2000]

60 min is still a good baseline for boiling, but the conventional "wisdom" of a hard rolling boil has been proven to be unnecessary, wasteful, and ultimately counterproductive. A solid simmer is sufficient, as long as there is visible circulation and mild disruption of the surface.
I still usually end up boiling off 8-10%, but am still trying to improve that.
So 7.5 gal into the kettle expecting 6.75 post-boil after an hour. It's still higher than necessary, but I find it hard to fine tune a gas burner to exactly the sweet spot.

 

[brewbama]

+1. I start with 7.5 gal in the kettle and plan for 6.5 gal post boil. That gives me a gallon of waste with the trub for 5.5 crystal clear gallons into the fermenter. Half a gallon to the fermenter trub for a 5 gallon keg.

 

[mkopec1]

I would love to see what type of boil they employ in a mega brewery that makes the watered down stuff like Budweiser, and their numbers, since in order to make that beer have perfect balanced taste and be consistent as it is they are probably doing things right.

 

[Genuine]

With all that I've learned over the years about boiling, the main reason I'm doing it is to increase the gravity. I supposed I could do a 30 min boil and use a bit more grain to make up for it.

 

[Vale71]

Systems employed at that scale don't even bear a passing resemblance to a boil kettle (the wort doesn't even get close to boiling temperature) and their numbers are simply meaningless for homebrewers.

https://www.kaspar-schulz.de/en/inn...ystem-schoko-/gentle-boil-system-schoko-.html

 

[Robert65]

I would love to see what type of boil they employ in a mega brewery that makes the watered down stuff like Budweiser, and their numbers, since in order to make that beer have perfect balanced taste and be consistent as it is they are probably doing things right.

The "bigs" do all sorts of things to reduce the amount of heat applied, from boiling under reduced pressure to achieve rapid evaporation of volatiles, to using mechanical agitators to get circulation without a full, rolling boil, and more. A "dynamic, low pressure boil," where pressure is repeatedly increased slightly and partially released to create massive releases of bubbles, can achieve all the desired results with only a 4% evaporation rate, and while temperatures will rise above atmospheric boiling temperature, the boil time is so drastically reduced (just over 30 minutes) that total thermal loading is much less. Another technique (pioneered by the Bud guys) is "wort stripping," in which the boil can be drastically shortened because on leaving the kettle, the wort is sheeted or sprayed through a chamber with a counter flow of hot, inert gas, and it is at this point that volatiles are removed. While none of this can be replicated by us, it does show the extent to which professional brewers are focused on reducing as far as possible the amount of heat applied to the wort. While of course one benefit is energy savings (offset by initial capital expenditures,) the primary goal is improving wort quality, reducing color and increasing flavor, aroma, textural and foam qualities, and stability.

 

[fendersrule]

My boil off is 1.75g per hour outside using propane.

But this is with a 20 gallon spike kettle making 5g batches.

I do a low roiling boil. If it splashes, then it’s too hot.

 

[J_Flint]

My boil off is 1.75g per hour outside using propane.

But this is with a 20 gallon spike kettle making 5g batches.

I do a low roiling boil. If it splashes, then it’s too hot.

Why such overkill on the kettle?

 

[balrog]

For "watery" beer, the first thing you should investigate is water chemistry. You possibly need to increase your chloride and/or sodium.

You may also consider step mashing and reducing your carbonation if it's too high.

Just wanted to jump in and second this. When I was having issues in the beginning with watery ambers and porters, I was told to "add some brewers crystals" which was a pkg of brewcraft stuff that was mostly gypsum and cacl (nowadays if you look for brewcraft brewers crystals you get sugar/malt substance; the stuff I had said "1 TSP per gallon increases hardness of water 889 ppm, Calcium Sulfate (Gypsum), Potassium Chloride, Magnesium Sulfate (Epson Salts), 135 ppm Ca++, 388 ppm SO4—, 19 ppm MG++, 183 ppm K+, 185 ppm CL-)

Subsequently I tested my water which turned out to be darn near RO with 3Ca 6Na 7Cl. But the addition of salts did help immensely with flavor and wateryness.

 

[fendersrule]

Why such overkill on the kettle?

BIAB + the ability to make double, if not triple batches.