Boiler dead space - hops make for increased or lower loss?

[shearclass]

Hi

My boiler has a dead space of approx 2 litres. I am doing a test run on it now with just water before i jump into my first extract brew. I am too much of a worrier to just do an extract without having everything set up in my mind and on beer smith etc!

As i say, it has a two litre dead space. However, in reality, the bottom of the boiler will be filled with hops once the boil has finished and the wort has been chilled. Does this mean that i will have, in reality, less dead space?

Hops take up volume, so there will be less dead space for the wort, meaning less loss. However, hops absorb water, so there is more loss.

Sorry for the rambling, but in summary, do hops in the dead space mean that

a) total loss is decreased (due to less dead space)
b) total loss is increased (due to hop absorption)
c) total loss is largely unaltered (so in this example will remain about 2 litres)

Thanks for reading.

 

[fbsf]

Having done my first extract yesterday, I can say with certainty that the hops will both a) absorb water, and b) roll around with the boiling water and not stay on top, so not help with reducing evaporation!

I was doing a 4.5L boil for 60 mins and lost about a litre, if that helps.

 

[31bb3]

You will lose some to dead space and some to the hops absorbing the liquor don't forget the more hops you use the more loss prob lose 1L to the hops

 

[bobsbeer]

The amount of loss to your dead space will depend on where your drain is. While the hops do take up space they are full of liquid which drains out. You are not going to get every drop and you would not want to try, but the lower your drain the better.

 

[Good Ed]

The biggest loss of wort during the boil to hops is by absorption; I work on these figures, 100g of hops displace 100ml and absorb 1.5L of wort.

 

[shearclass]

The amount of loss to your dead space will depend on where your drain is.

I have measured this as approx 2 litres in my very very old (my grandad's) burco boiler

The biggest loss of wort during the boil to hops is by absorption; I work on these figures, 100g of hops displace 100ml and absorb 1.5L of wort.

Thanks for those figures.

So in theory, a brew using 125g hops would mean that I would have no loss to dead space, as my 2 litre dead space would be consumed with the hops and their absorbed water.

Therefore, 125g or less of hops and I am losing 2 litres, either to hop absorption or to dead space. more than 125g hops then I will need to adjust my starting volume appropriately.

That gives me a good guide to be working on.

nd b) roll around with the boiling water and not stay on top, so not help with reducing evaporation!

Thanks, I wasn't thinking hops would stop any evaporation, so not worried about that. I have a lid for my boiler, but i am sure I have read somewhere something about leaving the lid off when boiling, for some reason. I will need to investigate!

 

[bobsbeer]

Yes do leave your lid off. Expect steam but don't put the lid on, as you are evaporating some of the nasty material.

 

[jonnymorris]

Thanks, I wasn't thinking hops would stop any evaporation, so not worried about that. I have a lid for my boiler, but i am sure I have read somewhere something about leaving the lid off when boiling, for some reason. I will need to investigate!

You need to let the Dimethyl sulfides (DMS) evaporate by leaving your lif off during the boil.

 

[shearclass]

Expect steam but don't put the lid on, as you are evaporating some of the nasty material.

You need to let the Dimethyl sulfides (DMS) evaporate by leaving your lif off during the boil.

Thanks. Is this something from the hops or from the wort? If the lid was left on, what sort of off flavour would this DMS make for?

 

[jonnymorris]

From John Palmer...

Dimethyl Sulfides (DMS)/ Cooked Vegetable Flavors
Like diacetyl in ales, DMS is common in many light lagers and is considered to be part of the character. DMS is produced in the wort during the boil by the reduction of another compound, S-methyl-methionine (SMM), which is itself produced during malting. When a malt is roasted or toasted, the SMM is reduced beforehand and does not manifest as DMS in the wort, which explains why it is more prevalent in pale lagers. In other styles, DMS is a common off-flavor, and can be caused by poor brewing practices or bacterial infections.

DMS is continuously produced in the wort while it is hot and is usually removed by vaporization during the boil. If the wort is cooled slowly these compounds will not be removed from the wort and will dissolve back in. Thus it is important to not completely cover the brewpot during the boil or allow condensate to drip back into the pot from the lid. The wort should also be cooled quickly after the boil, either by immersing in an ice bath or using a wort chiller.

 

[shearclass]

Thank you very much for that.

 

[jonnymorris]

No probs. Good question by the way. I've been wondering the same thing. I guess its even more significant as it relates to a mash tun given it'll be full of grain thereby reducing the dead space as compared to the initial measurement with no grain. I assume, however, it may be less relevant as you continually dilute the wort whilst sparging.

Have you considered measuring your boiler's dead space with hops included, i.e. after a brew?

 

[The Goatreich]

Is it ok to cover the boiler while it's coming up to boil, then removing the lid?

 

[jonnymorris]

Is it ok to cover the boiler while it's coming up to boil, then removing the lid?

In a word, yes.

 

[The Goatreich]

Cheers!

 

[shearclass]

Have you considered measuring your boiler's dead space with hops included, i.e. after a brew?

This si a very sensible suggestion. I haven't done my first brew yet, but when I do I will measure dead space with hops in boiler. I've done loads of ktis, but not yet done my first extract. Will be doing it very shortly.

As I will jsut be doing extract, I (thankfully!) do not need to worry about a mash tun just yet.