OG Higher than expected - thoughts?

[DominicRL]

Hi Folks,

So I’ve recently brewed a malt miller all grain kit, the ‘proud griffin’. I try to alternate between recipes (to learn styles) and my own innovations. Usually these kits are bang on the money for OG, but my last brew (23l batch for a supposed 1.048 OG) has led to a 22.8l batch with a 1.055 OG (taken at ferm temp, directly from the boil kettle). Both the recipe, and my own calculation confirm 1.048 is to be expected, so how has this happened? Ive edited my process a little by adding several rounds of mixing/whirlpool to the mash over the 60mins, having had an issue with a stuck sparge in the new year, but this is an efficiency improvement of nearly 15% which seems significant.

In theory higher alcohol/efficiency is great, but predictability is my key aim. Have you guys experienced anything similar, how can I make this more predictable?

Best,
Dominic

 

[Rodcx500z]

Could be MM got their weighing of grain wrong ie to much nobody is perfect

 

[Sandimas]

In a word, no, I've not experienced anything like this in over 200 AG brews. I got a 3% efficiency increase when I changed grain suppliers, and then a 1% drop when I changed again, but 15% is huge. And it sounds like you know your kit and your process, so it can't be that. I'd go with the above - did they weigh it out correctly?

 

[Baldylocks Brewery]

Hi Dom, what was the efficiency? Is it something achievable otherwise it does point in the direction of Rod’s point.
My OG is generally all over the place, yesterday 0.6 lower, which is suspect is me not being able to use a set of scales!

 

[DominicRL]

In a word, no, I've not experienced anything like this in over 200 AG brews. I got a 3% efficiency increase when I changed grain suppliers, and then a 1% drop when I changed again, but 15% is huge. And it sounds like you know your kit and your process, so it can't be that. I'd go with the above - did they weigh it out correctly?

I was thinking exactly this, a couple points up or down wouldn’t throw me but 7 points get obscene. In truth I didn’t check, have never had an issue so didn’t think too - a lesson for the future!

 

[DominicRL]

Hi Dom, what was the efficiency? Is it something achievable otherwise it does point in the direction of Rod’s point.
My OG is generally all over the place, yesterday 0.6 lower, which is suspect is me not being able to use a set of scales!

About 86/87% I believe (from 5kg of pale malt that would be right) which would be higher than anything I’ve got before, though a combo of a hop plate and mash whirlpooling is new. Will see if I can recreate this with a recipe I’ve checked the weight of myself!

 

[Rodcx500z]

I worked in the baking industry for 30 years and, believe me when i say all the problems we encountered were with bought in ingredients

 

[MashBag]

What was the mash temperature?

 

[DominicRL]

What was the mash temperature?

Fairly standard for a bitter - 64(60) and 75(10) for mash out.

 

[DominicRL]

I worked in the baking industry for 30 years and, believe me when i say all the problems we encountered were with bought in ingredients

Funnily enough I worked in ice cream manufacturing for a bit and it was the exact same thing, if the milk fats weren’t varying wildly then the ingredients were lost somewhere in Europe… as suppliers go I’ve always been impressed with MM so will forgive them (it’s more alcohol after all…) and make a note to weigh again for myself in future!

 

[RoomWithABrew]

Was it fully mixed when you took the sample. Stratification occurs quickly.

 

[DominicRL]

Was it fully mixed when you took the sample. Stratification occurs quickly.

Interesting idea, so I took the sample directly as I was filling the fermentor (about 5/23l had gone in so not really the beginning or end) about 10 mins after the end of the boil.

 

[Sadfield]

My efficiency jumped up 9% when I started doing water treatment, although it was 12 brews in, so general familiarity with the process may also have helped. It was at that point I started buying base malt by the 25kg sack, which undoubtably aided consistency.

I don't think it's coincidence you've seen a change upon introducing two alterations to your process.

 

[DominicRL]

My efficiency jumped up 9% when I started doing water treatment, although it was 12 brews in, so general familiarity with the process may also have helped. It was at that point I started buying base malt by the 25kg sack, which undoubtably aided consistency.

If I could get away with it I definitely would, it took intensive negotiations with the partner to find a home for the fermenters…

 

[foxy]

I would put it down to user error if there was enough extra grain to gain an extra 7 points then the volume into the fermenter would be far less than expected due to loss to grain. Always take your gravity reading from the clear wort in the fermenter. I agree with RWAB taking it from the kettle doesn't give a true reading. Can you work it back from pre boil volume and SG.

 

[Mash Monster]

FWIW I too have just completed a MM true to style bitter and had an OG of 1.045 expected 1.040 by Malt Miller (1.043 Brewfather) not quite the 7 points over but still high. I was also nearly 25L instead of 23L into the fermenter.
TBH I was expecting it to be on the low side as I changed out my 3Kw heating element for a 2.2Kw one and adjusted my equipment profile in Brewfather as well .
4.5 KG of grain
Mashed at 67°c 60 min with a mash out @ 75°c for 10 mins with a 60 min boil .

It’s just finished fermenting with a FG of 1.010 giving an ABV of 4.6 instead of the 4% predicted tastes good too !

 

[foxy]

FWIW I too have just completed a MM true to style bitter and had an OG of 1.045 expected 1.040 by Malt Miller (1.043 Brewfather) not quite the 7 points over but still high. I was also nearly 25L instead of 23L into the fermenter.
TBH I was expecting it to be on the low side as I changed out my 3Kw heating element for a 2.2Kw one and adjusted my equipment profile in Brewfather as well .
4.5 KG of grain
Mashed at 67°c 60 min with a mash out @ 75°c for 10 mins with a 60 min boil .

It’s just finished fermenting with a FG of 1.010 giving an ABV of 4.6 instead of the 4% predicted tastes good too !

And what was the weight of fermentable grain?

 

[Mash Monster]

It was 4.5KG

 

[foxy]

It was 4.5KG

So no other grains other than base malt?

 

[Mash Monster]

So no other grains other than base malt?

I’ve DM’d you