temp dropped too far?

[deano2469]

Hi guys, I made a brew yesterday of DR Smurtons ale, BIAB. i had a basic recipie for a 20lt batch and used brewmate to increase the batch to around 44lt. I started with my 50lt keg for the mash, started with 35 lt of water to 68deg, added bag and grain, almost 10kg. I wrapped vessel and left for an hour. Twice previously this method worked and lost only 2 to 3 deg. This time however it went down to about 58 deg, i warmed it up to around 75 as i lifted out the bag but i feel i might have ruined a brew. I think because the grain bill took up more space than the usual 6-7 kg there was less water and so cooled quicker?...not sure. anyway as raised temp to boil, i added another 10 lt of heated water through my strainer to sparge grains and to bring level up. I went through the hop additions etc for the next hour and lost maybe 5-5 lt in the boil...i thought all was going ok. after it cooled overnight i syphoned the mix into my fermentor to find i only had about 35 lt. i added another 10 lt to bring final total to 44lt in fermentor. This method might seam strange but i want to end up with two kegs each brew. I am not worried about alcohol content too much anything above 4% is fine.Brewmate said FG should be 1.050 and i got closer to 1.038, I am however concerned about any loss of flavour and any issues because my mash got too cool....any advice would be gold, its only my third brew, first was the best, second found out what mash hopping was...to my detriment, this time i think i'm about to learn something else.

cheers

 

[klangers]

If you're doing immersion mashing, you need to increase the temperature of your mash water to a temperature higher than what you want to mash at. This is because the (relatively) cold grist will absorb water and cool it. The temperature of the water when you put your grist in is known as the strike temperature.

There are ways to calculate the strike temperature such that after adding all your grain the temperature has fallen to your ideal mash temperature.

In addition, grain absorbs a lot of water. There are ways of calculating this too.

I suggest you have a look at a few online brewing calculators to get your head around what's going on.

Cheers

 

[manticle]

First the volume: You started with 35 L of liquid and 10 kg of grain? 1 kg of grain will absorb around 1 Litre of water so you now have 25 L. You add back 10 L so you have 35 again, then lose another 5 L in the boil, taking you to around 30. As the liquid cools, you would lose a touch more as the liquid contracts so I'm surprised you even got 35 L, not including trub but you might have mismeasured the volume. Topping up with water in the fermenter might explain why the gravity was much lower than expected and will also give you a thinner, less flavourful beer

As for the heat loss - it really depends what temp it was at in the beginning and how long it remained there before dropping. Did you measure the temperature of the mash after hydrating the grain?

 

[deano2469]

Thanks Klangers, I will keep an eye out for those calculators, I really needed to check the temp after i hydrated the grain too manticle. I thought that absorption might have been an issue. The level was a lot lower than i expected from prior brews I will endeavour to make a measuring stick as inside the keg I'm using for boiling its easy to just guess and miss. I was hoping the large grain bill would compensate in some way for keeping flavour and alcohol up...is that a stretch?would it be better to add water to the boil or to the fermenter ? would it make a difference?. It did taste pretty flavoursome , more than the last brew but i guess only time will tell. i need to be more observant .

thank you

 

[n87]

If i add water for the boil, i will pour it through the grain that is suspended above the pot.
this way, you also have the benefit of extracting just that little bit more of the sweet stuff.

also, adding before the boil will kill any nasties hiding in the water... this being half the reason for the boil

 

[deano2469]

cheers n87, i did a sparge with about 10 lt, should have gone a bit more.

 

[deano2469]

Just a follow up to this brew...oh my god, tastes great . put it on tap after 17 days under house ,cooled for a day in fridge then gassed up overnight. drank all day watching Bathurst, friends thought as i did that it was a great tasting beer. FG ended up being 1.002 from 1.038 so about 4.5%?. I will watch the pot more often next time and im looking for a grate or strainer to put in bottom of kettle to keep bag off bottom if i need to add heat.Going to try a copperhead ale next...wish me luck, its close to amount of grain so will practice what i have learnt from you guys...

Thanks again all.

Deano

 

[klangers]

Good to hear mate.