Mash efficiency or cooker inefficiency?

[brettski]

Hi all,
Tried my hand at BIAB this weekend, my mash steps were:

1. Strike at 70C
2. Stir for 5 minutes to get temp down (it was a hot day)
3. Mash at 67C for 70 minutes
4. Mash out at 75C for 10 minutes
5. Drip and gave the bag a good squeeze

Not knowing what to expect being my first time, I calculated around a 70% efficiency for a OG of 1.058. What I got was 1.068 (after adjusting for temp). This means my efficiency in theory would be about 80%. This seems unlikely as I didn't sparge. Does this sound right to you guys? Could another explanation be that my cooktop is inefficient and is boiling off more water making the end result more viscous?

 

[wereprawn]

Not sure why you would blame cooker inefficiency for a high boil off. You need to provide more details on volume of liquid before and after the boil and ingredients ect to make it easier for others to help.

 

[Dunkelbrau]

What volume were you expecting and what volume did you get?

 

[brettski]

Sorry, I forgot I started this thread. I shouldn't start threads when I've been into a few home brews
My mash volume was 16.6L, with 13.3L going into the boil. I was expecting it to boil down to 11L but I got about 9.5L.

I reckon I need to work out the boil rate of my pot before I jump to any conclusions.

 

[sp0rk]

I regularly hit 80% with decent malts with my BIAB rig, no sparging
It's not out of the question

 

[MHB]

Efficiency is pretty much how much you got out of the malt / what the standard test says you could get.
the amount of water the extract is dissolved in isn't really part of the calculation.
but the amount of malt you used is necessary to calculate efficiency, so how much malt went into the brew?
Mark

 

[Adam Howard]

If you were expecting 11 litres of 1.058 and got 9.5 litres of 1.068 wort then you'd probably end up bang on your estimate by topping up with 1.5L of fresh water. I don't have software in front of me to test the figures but you'd get pretty much a 10% drop in gravity by adding 10% more volume. It's just that your boil rate is higher than expected which isn't a big deal and can be factored in with a greater volume of strike water in your next batch to hit your desired final volume.

 

[Dunkelbrau]

Volume doesn't change the efficiency , but it is a part of the calculation. If you dilute, you have to say you got 11L of 1.058 which will workout to be roughly the same in the efficiency calculation.

I wouldn't worry about it right now, I'd plug in that number (and the losses you recorded including the extra 1.5L of boil off) and brew again, record losses, check calculation and try and nail whatever efficiency you are getting, it really doesn't matter how good it is, but that it is consistent.

Good luck

 

[Bribie G]

Agree with all above. For a "regular" brew of around 1055 I have a mark on the sight tube of my urn for level of strike water, and a mark lower down for post-boil volume that fits my no chill cubes.

I get good consistency and also hit 80% regularly.

According to my software I should use 31L of strike water, but that mark on my sight tube is actually 33L, It's all in the boil off rate as you have found.

 

[Adam Howard]

Volume doesn't change the efficiency , but it is a part of the calculation. If you dilute, you have to say you got 11L of 1.058 which will workout to be roughly the same in the efficiency calculation.

Volume is integral to efficiency calculations. Whether you're measuring mash efficiency as pre-boil volume and gravity or as brewhouse efficiency post boil and chilling.

 

[BrewedCrudeandBitter]

My efficiency was absolutely woeful on my last brew.

I was expecting an OG of about 1.057 but after transferring from the cube to the FV I checked the gravity and it was 1.048. Not even 60% efficiency. The worst part was I was trying hard to increase the efficiency and taking extra steps that I hadn't taken previously after reading up on increasing BIAB efficiency.

 

[Dunkelbrau]

Volume is integral to efficiency calculations. Whether you're measuring mash efficiency as pre-boil volume and gravity or as brewhouse efficiency post boil and chilling.

I know. I was saying a change in the volume doesn't change it. So diluting, or boiling down more will mean the same efficiency.

 

[bronson]

My efficiency was absolutely woeful on my last brew.

I was expecting an OG of about 1.057 but after transferring from the cube to the FV I checked the gravity and it was 1.048. Not even 60% efficiency. The worst part was I was trying hard to increase the efficiency and taking extra steps that I hadn't taken previously after reading up on increasing BIAB efficiency.

About 8 months ago I had a similar problem and it was related to how coarse the brew shop was milling my grain.
After picking everyones brains on here I took a punt and bought a Grain mill and my efficiency went from 50% to consistant 77% to 81%. Not saying this will sort you out put its definatly something to consider.
B

 

[BrewedCrudeandBitter]

Yeah good point. I get all my grain milled at craftbrewer and I assumed it would be fine?