Does the size/strength of a boil affect the beer?

I have a gas stove but unlike many I've seen with a small burner, two medium burners, and a large burner, mine has four small/medium burners. This means I haven't been able to get a really hearty boil going. To put it in perspective, I have to cover the pot to get the boil going; once going I can uncover it but it's a lazy roll not a vigorous boil; I have never had to worry about boil-over (and I dare say I could even cover the pot and it wouldn't boil over).

Is this too weak a boil? To what degree does the strength/size of boil matter?

Does the surface look lumpy? Or is it only little bubbles slowly rising? You dont need a really vigorous boil, but you want the fluid moving consistently. The boil has an effect on hop utilization, flavor (melonoidin formation, and driving out nasty voliteles like DMS), etc.

If you cant hit a proper boil, consider boiling less and adding sterile water when you chill.

If you listen to the Brewing Network regularly, Jamil occasionally mentions that he doesn't get a very vigorous boil going. He says that the important thing is that the wort gets moving and turning over from the bottom to the top. As long as it is boiling, you're burning off the precursors to DMS, isomerizing the alpha acids from the hops, etc... You should be fine.

It definitely rolls; if I cover the pot I can get a better boil going. I think a 2.5-3 gal. partial boil is about max for my stove, though...

I read from time to time about "getting a raging boil" going so I was a bit worried it affected the beer.

I don't think my stove could boil more than 5gal at a time but then I only have a 17qt Bk... I do AG 5gal batches and collect all my runnings and give it a good stir and split it into two 3gal boils and split all my hops and any other additions.. It adds more time to the brew day but I feel more confident about getting rid of all DMS and getting full extraction from the hops this way. I want to go all electric eventually with a 7.5gal BK...

On the 'Head Retention' podcast JP said something about the high heat load possible from using propane jet burners can degrade proteins and cause excessive break. Not really sure exactly what he meant though. I was boiling my wort pretty hard (with a jet burner) and after listening to that I've been boiling fairly gently and not as long...but those beers aren't done yet (only started this a few batches ago) so can't comment yet.

SpanishCastleAle said:

On the 'Head Retention' podcast JP said something about the high heat load possible from using propane jet burners can degrade proteins and cause excessive break. Not really sure exactly what he meant though. I was boiling my wort pretty hard (with a jet burner) and after listening to that I've been boiling fairly gently and not as long...but those beers aren't done yet (only started this a few batches ago) so can't comment yet.

Click to expand...

I made a kolsch for the second time last weekend and decided to get a good hearty boil going for this batch. I noticed I had a lot more cold break in my fermenter this time. Usually I just get a nice rolling boil, nothing to vigorous. I'm going back to that.

When I first started brewing, I put my pot in between two burners on the stove, and cranked them both up. It took for-freaking-ever to get the boil going... and it wasn't that fantastic a boil either.

I may live in an apartment, but a turkey-fryer burner and a propane tank was a must-buy for me, to get the proper BTU's to get the boil going, and the brew day over and done with.

jwic said:

It definitely rolls; if I cover the pot I can get a better boil going.

Click to expand...

Not good to boil wort in a covered pot.

_

wildwest450 said:

Not good to boil wort in a covered pot.

_

Click to expand...

Because of possible boil-over or for some other reason?

wildwest450 said:

Not good to boil wort in a covered pot.

_

Click to expand...

Is it a problem with extract?

During the boil compounds are boiled off that you don't want in your finished product. If you cover it they have no where to go, causing off flavors. If you want a better explanation do a search, it's been covered a million times.

_

edmanster said:

Is it a problem with extract?

Click to expand...

Good question, I assumed it was all grain. Since extract is already processed, I'm not sure it would be a problem. Better to be safe than sorry.
I do leave the lid on until the wort reaches 205f, as my water boils at 208. That will help it get up to temp faster.


_

Sorry, I was unclear, too. I do extract; I do not keep it covered the entire time (just until it gets a decent boil going).

jwic said:

Sorry, I was unclear, too. I do extract; I do not keep it covered the entire time (just until it gets a decent boil going).

Click to expand...

No problems with that.

_

What defines a good rolling boil? I found a few youtube videos on boils. I think even this is at times TOO vigorous?



Where this is definitely too vigorous

The first one looks like my boil. I like the top to roll without wort being flung out of the pot. Although with an electric element it's a continuous rolling, not an occasional big bubble coming from the bottom.

_

Jwic, your probably fine man. Much more important factors,espescially if using extract

jwic said:

Sorry, I was unclear, too. I do extract; I do not keep it covered the entire time (just until it gets a decent boil going).

Click to expand...

I believe extract is already boiled.

If you listen to the Brew Strong podcast about melanoidins they talk about how these compounds are formed as related to the boil too. They also talk about the vigorousness of the boil and evaporation rate. I think it's more for advanced knowledge, but to answer the original question, I think it's a yes.

Krrazy said:

If you listen to the Brew Strong podcast about melanoidins they talk about how these compounds are formed as related to the boil too. They also talk about the vigorousness of the boil and evaporation rate. I think it's more for advanced knowledge, but to answer the original question, I think it's a yes.

Click to expand...

Agreed - but not as important for extract. In fact - most of the extract shouldnt be added to the boil until the end.

All grain, you want a healthy boil.

I won't claim to be an authority but 212 is 212, whether the boil is lazy or vigorous. Any differences, therefore, have to come from the mechanical aspect of more "stirring" in a vigorous boil. More heat certainly puts more energy into the system so more wort will boil off in an hour You will have to adjust your process by adding more starting liquid to achieve a target final if you crank up the heat.

^^^ Yes and no. When the bottom of a kettle is 250F, you're going to get some different reactions in the wort than if the kettle bottom is 550F, for example. A local brewery superheats their kettle to a crazy high temp before dropping their wort for a scotch ale in, causing intense caramelization in a short period of time. You may claim the liquid never gets above 212, and you might be right, when looked at one way, but to argue this makes no change in the finished product is very much incorrect.