Effects of too vigorous boil

[JONNYROTTEN]

Lately I've been getting a sort of grainy bitter taste in my beers. I've never had this issue until lately. My PID is on the fritz and has only been running at 100 full power for the boil. Could this be the issue?? The only other thing I can think of is grain storage. They've been in an open bag for a few months in a warm/hot upstairs bedroom. They smell and look fresh so I'm thinking that's not it. But those are the only 2 differences in my brewing..less fresh grain and full power boils.

 

[IslandLizard]

Possible scorching and more caramelization?

 

[JONNYROTTEN]

Possible scorching and more caramelization?

I doesn't taste burnt. I have a small false bottom that keeps the bag off the element

 

[C-Rider]

Less wort to ferment. Less beer to drink.

 

[JLeuck64]

I too have wondered if the different taste I noticed in a previous brew was due to an aggressive boil or not. It pays to keep mental notes during brew day ( ;

 

[JDXX1971]

Yeah I would like to hear more on this too. I had my first brew days ever earlier this week and I had to boil a little longer and harder than I expected to hit my #'s. Hopefully there will be no bad effects though I thought I read somewhere before that boiling too hard could raise your potential f.g.? Something about converting sugars into less fermentable ones????? I guess I will be finding out soon with three batches in the fermenters.

 

[wilserbrewer]

How many watts, how large a kettle, and how many gallons are you boiling? Curious how vigorous you are boiling?

 

[JONNYROTTEN]

How many watts, how large a kettle, and how many gallons are you boiling? Curious how vigorous you are boiling?

5500w, 20 gallon kettle,water after mash out is around 13 gallons. It used to be a nice rolling boil but its definitely more violent now. When the Pid was working I ran it at 75% and lost around a gallon. Now that's its running on full power I'm loosing around 2 gallons. Which brings up another point. Would adding more tap water to top off give this grainy bitter taste? I top off right before chilling to get to my known numbers to reach 6 gallons each bucket. I've also been raising and lowering the chiller to help cool faster and its been splashing around a bit. Then pitch the next day. I wouldn't think oxidation pre yeast would be an issue.I'm also not getting tons of hop flavor even though I've been doing NE style IPA brews which I would think was a water quality issue but my water here is good and never had this issue before.

 

[wilserbrewer]

2 gallons boil off doesn't seem extreme to me, idk sorry no help.

 

[day_trippr]

fwiw, 2 gallons/hour is where I've dialed in the boil-off on my 20g G1 BK after a half-dozen batches...

Cheers!

 

[ba-brewer]

Some malts just taste more grainy than others to me, rahr 2 row and castle pilsner in particular. Giving it more time to age normally gets rid of it for me.

I get about 1.5gal boil off in 15gal kettle and haven't noticed any issues.

I have heard Jamil on the brew strong show mention too high of boil off can cause trouble but he did not elaborate.

 

[techbrau]

http://forum.germanbrewing.net/viewtopic.php?t=440

 

[brewbama]

I've read the optimum boil would look more like a simmer vs a volcano. ^^ These guys say a 90 min gentle or rolling boil. YMMV

 

[day_trippr]

http://forum.germanbrewing.net/viewtopic.php?t=440

Two variables changed from the first to second batch - boil time (halved) and "vigor".
Not being able to judge "vigor" I'm going to go with the boil time as being more responsible for the deeper color...

Cheers!

 

[techbrau]

That's true, but in my experience they are somewhat exchangeable. Unless you can measure thiobarbiturate index (TBI) like real breweries do, total boiloff % is a decent proxy for quantifying the heat stress that the wort is exposed to during boiling. You can get the same boiloff % with a shorter, vigorous boil or a longer, less vigorous boil. A long, vigorous boil is of course going to be the worst.

When I went down to a 60-70 minute boil with ~15% boiloff, I still got more color development and flavor deterioration than I wanted, but I don't have the pictures to show it. It wasn't until I moved to a 60 minute boil with 8-10% boiloff that the flavor (and color) stayed intact. Go too far below 8% boiloff and you will end up with DMS in the wort.

Try it yourself, YMMV...

 

[day_trippr]

I've never done a two hour boil, and the "vigor level" (if there is such a metric) I go for could be characterized as "moderately rolling". The "fizzy yellow pisswater" (aka Cream Of Three Crops) I brew for hop-adverse visitors stays "Bud Yellow" forever, and that recipe would make it easy to see effects of hard boil reactions and post-boil oxidation. So I'm comfortable with my process...

Cheers!

 

[techbrau]

For what it's worth, I see a lot more color pickup from a hard boil when using a low oxygen process. But I believe that's largely due to the fact that low oxygen wort starts off significantly paler in the first place.

See these links if you don't know what a low oxygen process is

http://www.germanbrewing.net/docs/Brewing-Bavarian-Helles-v2.pdf
http://forum.germanbrewing.net/
https://www.homebrewtalk.com/showthread.php?t=580532

 

[beersk]

Go too far below 8% boiloff and you will end up with DMS in the wort.

Try it yourself, YMMV...

Which totally explains why German breweries target 4-6% boil off, so says Kunze.

 

[techbrau]

Right, but they are often boiling under pressure for a very short amount of time (~30 min) at hotter than 212F and following up the boil with a scrubbing process to strip DMS and other undesirable volatiles.

For a conventional boiler like a homebrew kettle, 4% evaporation is probably too low and would result in residual DMS. You can get away with 6% if you're careful.

 

[beersk]

Right, but they are often boiling under pressure for a very short amount of time (~30 min) at hotter than 212F and following up the boil with a scrubbing process to strip DMS and other undesirable volatiles.

For a conventional boiler like a homebrew kettle, 4% evaporation is probably too low and would result in residual DMS. You can get away with 6% if you're careful.

Hmmm interesting point... I think I've been getting in the 6-8% range, with a 45-60 minute boil time. Haven't detected any DMS yet, but it could be there in very small amounts...