AG#5 Evaporation Loss !!

[brewster324956]

Hi All.

Have just completed AG#5 Caledonian Dauchers G.Ws recipe.

Ended up with 20lrs wort after the boil with ag 1042.

Started with 32 litres treated water.

Now my set up is crude compared to many on here as I mash on range cooker “no mash tun……..yet” and use Electrim boiler recent addition .

I boil 20ltrs in boiler with additional 8ltrs ish of wort boiled on Rayburn for top up .I don’t add more wort to boiler as wort slops over sides or sperts out of lid hole ,found trying to adjust the stat a pain just seem to get a very vigorous boil .

Have siphoned off 20ltrs in fv just under 19ltrs leaving trub behind ,GWs book says 23ltr brew length.

Now I tend to brew short anyway and have never been disappointed with results ,however in keeping with good practice etc I would like to know why I’m not hitting 23ltr target ,I thought my new boiler would solve some of my evaporation loss problems.

Pitched Yeast last night into very clear golden and fantastic smelling wort .

Any thoughts !!

:

 

[Mark1964]

We had the same boiler as you and the thermostat was also a problem. We never used it for mashing. As for evaporation we generally lose 11 percent per hour so our boil volumes starts at around 33 litres to end up with 25 but sometimes we still end up short

 

[Runwell-Steve]

Hi

You seem to be a bit low on the volume of water you are starting with.

To work out your losses overall you can use this as a rough guide.

You will lose 1 litre per kg of grain in the Mash Tun plus any dead space.

You will lose 1.5 Litre of water per 100g of hops used in the boiler plus dead space.

You will lose 10 - 15% per hour of the boil, by the way you shouldn't have the lid on whil you are boiling.

You are starting with 28 Litres pre boil, as you are boiling across 2 pans your surface area will be greater so you could esily get a 15% loss over 60 minutes, if you are boiling for 90mins this is 22.5% loss.

So 28 litres, minus 22.5% = 21.7 Litres, less the 1.3 litres you will lose to hop absorption will give you 20.4 Litres.

Essentially If you want to end up with 23 Litres of wort post boil, you actually need 24.5 litres in the boiler(s). To get 24.5 Litres post boil you need to start with 31.6 litres pre boil, assuming the same losses that you are currently getting.

That means you need approx 35.6 litres to start with prior to Mashing, rather than the 32 litres you are currently starting with.

 

[brewster324956]

Thanks Mark,

I'm yet to be convinced with the new boiler but accept as stated it may be me :? ,although its ten times better than balancing stock pots on the range .

When I boiled 20 ltrs I ended up with about 16/17ltrs left.I've always lost more on the hob.

 

[brewster324956]

Thanks for the guide Steve :thumb:

So ending up just short of twenty litres wasn't as bad as I first thought ?

I usually place the lid on the boiler to stop evaporation,surely if I leave it off I would suffer from more wort loss ??

 

[markp]

I usually place the lid on the boiler to stop evaporation,surely if I leave it off I would suffer from more wort loss ??

The lid should be removed so that the boil can drive off DMS.
DMS tastes like cabbages apparently.

 

[brewster324956]

Thankfully never had the smell or taste of cabbages as I always taste post boil after taking sg,however will now brew lid off so to speak.

Thanks again :