Biab Og Issue

[whippee]

Hello all,

I did my second biab brew yesterday. I let the wort chill overnight and transferred to fermenter and pitched yeast today at 20 degrees. Before I pitched the yeast I measure the og and it was 1.032, which is pretty low. I decided to add 300 grams of ldme to increase the gravity.

I have used the brewmate software program and have attached the recipe for others to look at. I can only figure that my efficiency it crap, hence the low og, is this correct?

I would appreciate any feedback on this issue. I did a 60 minute mash and 60 minute boil.

Thanks in advance

View attachment Andys_Pale_Ale.xml

 

[RobH]

How many litres of water did you mash in & how big is your mash tun/kettle?

From memory you need a minimum 3:1 ratio of water to grain for mashing ... so 1 part grain 3 parts water - your 3.65kg of grain would have needed 11 litres of water to mash in.

I recently mashed 5kg (4kg grain + 1 kg boiled rice) in 10 litres of water as I forgot to take into account the space the rice would take up in my 15 litre pot & I ended up with a rather low OG of 1.026

I think the 2:1 ratio, combined with the total lack of circulation in the pot is why it ended up so low.... still made a great tasting beer though!

 

[McFeast]

How many litres of water did you mash in & how big is your mash tun/kettle?

From memory you need a minimum 3:1 ratio of water to grain for mashing ... so 1 part grain 3 parts water - your 3.65kg of grain would have needed 11 litres of water to mash in.

I recently mashed 5kg (4kg grain + 1 kg boiled rice) in 10 litres of water as I forgot to take into account the space the rice would take up in my 15 litre pot & I ended up with a rather low OG of 1.026

I think the 2:1 ratio, combined with the total lack of circulation in the pot is why it ended up so low.... still made a great tasting beer though!

what the! I am soon to do a similar mash with 35l water at 68degC (a 4kg grain bill and 1kg rice from a simple BribieG recipe) and then boil. this was a simple recipe and i thought it would be a better result than what you're suggesting for 10l. will definately be sparging based on these findings!

 

[whippee]

Thanks for replies,

I mash in a 19l pot. I added approx 10 liters of water.

I will check the gravity tomorrow after it all settles a bit and see what its like. When this beer ferments, will it be a lighter abv beer? Say a mid strength or something?

thanks

 

[RobH]

what the! I am soon to do a similar mash with 35l water at 68degC (a 4kg grain bill and 1kg rice from a simple BribieG recipe) and then boil. this was a simple recipe and i thought it would be a better result than what you're suggesting for 10l. will definately be sparging based on these findings!

Sorry, didn't mention that my final volume in fermenter was 20 litres ... so although I mashed in only 10 litres, I had to add water for the boil etc to get my final volume of 20L ... considering the grain would have soaked up a large part of that original 10L I rekon I diluted my mash runnings somewhere in the vicinity of 5L mash runnings to 15L water to get to 20L

If you are mashing 4kg grain & 1kg rice in 35L then I imagine you will have much much better efficiency that I did in only 10L of mash water

 

[RobH]

Thanks for replies,

I mash in a 19l pot. I added approx 10 liters of water.

I will check the gravity tomorrow after it all settles a bit and see what its like. When this beer ferments, will it be a lighter abv beer? Say a mid strength or something?

thanks

That's not too bad I suppose, but I guess it depends on which side of "approx" 10 litres that was. Did it end up bringing the liquid level in your pot right to the brim? Or did you have some room to spare? The reason I ask is that if you had room to spare, then you will know for next time with that amount of grain you can afford another litre or two of water in there.

A really rough guesstimate at your abv on the finished product ... my brews that have had an og like that end up being something like 3.5% ... which is perfectly fine with me as long as it tastes good!

 

[HeavyNova]

I'm next to BIAB and I too recently did a brew with woeful efficiency. Aiming for 1056 but I got 1030! I'm also brewing in a 19L kettle and only doing half batches (12L). I squeezed the bag, didn't sparge and left some wort behind with the break material - but still; 1030 is low!

For my next brew I plan to open the pot and bag and give it a few stirs throughout the mash. From speaking to a couple of people about this it seems that the 'damage' done from the drop in temperature isn't as bad as getting much better efficiency...if that makes sense. One way to find out.

 

[Thirsty Boy]

Your bag shouldn't be closed in the first place. The bag stays open and lines the pot like a bin-liner in your garbage bin. Lid goes ontop of open bag.

This means you can stir properly at mashing in and easily any time during the mash.

You stir - take a temp while stirring and if it has dropped... Turn on the heat and keep stirring till it isn't low anymore. No damage whatsoever from Temp loss incurred, and half a chance of decent efficiency because your mash has been properly mixed.

Remember with BIAB - all forms of it - you aren't mashing inside a bag, you are mashing in a pot, its just that the pot happens to be lined with a bag thats all. If the bag is interfering with the mash in any way at all, constricting, constraining, enclosing, limiting your access or your ability to stir , add heat, add liquid, take temps, take samples.... You haven't got it right.

 

[super_simian]

I'm next to BIAB and I too recently did a brew with woeful efficiency. Aiming for 1056 but I got 1030! I'm also brewing in a 19L kettle and only doing half batches (12L). I squeezed the bag, didn't sparge and left some wort behind with the break material - but still; 1030 is low!

Really? I'm on my 8th BIAB or so, and I'm constantly ending up with a higher OG than predicted. In fact on my last batch I played with the efficiency setting on Brewmate and it told me I had an efficiency in excess of 85%! Now, I am aiming for fairly low OG in most of my recipes, from about 1.038 to 1.048, so my L:G ratio means I am doing a thin mash, and I mash for 90min and sparge, but still... How fine are you crushing, what temp are you mashing at and is you thermometer correct are all viable questions here.

 

[radearling]

I'm with super, I can normally get about 75%, but I found plenty of stirring (a potato masher is good) and a 90 min mash does the trick

 

[bevdawg]

I've just done my 9th BIAB in a 40ltr pot, generally using around 33ltr water and grain bills around 5-6kg. Heated on the stove top, stirred heaps to begin then left to conserve the heat for 60-90 min (usually 90min). I end up with around 23ltr after boil and trub loss and almost always hit exactly 70% efficieny as predicted by Beer Smith. I feel like if you fill in ALL of the fields in Beer Smith (so work out all the relevent info for you mash tun, like trub loss, weight etc) it give's exact results, every time.

 

[bcp]

My biabs were all over the place in efficiency. Lows of 50%, highs of 70%. I think two things that helped the most:
1. Stirring - about half way through.
2. Changing my water chemistry. I use melbourne cardinia water, and found for something like a pale ale, i used some calcium (chloride or sulphate) and efficiency shot way up, to just over 80%.

 

[felten]

My biabs were all over the place in efficiency. Lows of 50%, highs of 70%. I think two things that helped the most:
1. Stirring - about half way through.
2. Changing my water chemistry. I use melbourne cardinia water, and found for something like a pale ale, i used some calcium (chloride or sulphate) and efficiency shot way up, to just over 80%.

Ditto, decent calcium levels and pH can play a big part in efficiency. I get 76-80 each time depending on the grainbill.

 

[megs80]

Agree, ph is far more important than water to grit ratio etc