Struggling to hit target OG

[Yabezag]

I am on my 60th Grainfather 30 brew and am occasionally struggling to hit Target OG at end of Mash. I suspect the grain mill as I have not changed anything else. Last night I was doing David Heath’s Mild. Target OG 1.035, I got 1.018. I have spoken to the supplier who delivered 5 grain bills in December. Will see what the next one does!
Any ideas?
Thanks
Gareth

 

[AJA]

That's massively out. First suspect would normally be the recipe, post on here if you would us to double check (although after 60 brews - unlikely).
Alternatively, is the G30 thermometer working correctly? Could you test against an old school thermometer?

 

[Agentgonzo]

It's hard to advise with such little information, but if it's your 60th brew, I guess we can rule out rookie mistakes like not crushing the grain.
It could be the grain. Take a look at your crush next time see if the crush is off (ie, are there any whole kernels in there).
AJA's comment about mash temp is a good one - always worth checking that with another thermometer. The same goes for measuring the temp of the sample you measured the gravity of.
How did you measure the OG? tilt/ispindel (which are notoriously unreliable), refractometer (could be out), traditional hydrometer. I have always wondered that the scale in the hydrometer just seems to be a bit of paper stuffed in there. I've always wondered what stops it slipping. Maybe it's worth just checking your hydrometer measures 1.000 in water?
If your supplier just delivers the bags and you stick them in the mash, maybe weigh one of them to check it does indeed weigh what you expect?

 

[Sandimas]

So you buy uncrushed grain and mill the grain yourself, with a new grain mill, and now you get a poor result? There is your answer.

 

[borischarlton]

I would suggest that you have not taken into account the new seasons malt and just how different in size each kernel is. We have seen a massive variation this change over. Most of the malt, the kernels are much bigger requiring a larger gap, conversely we have also seen the opposite in some malts. Changing mill settings is a constant for us but "home type" mills are a little more forgiving but I bet that is the cause.

Plus, if you are receiving uncrushed grain bills, where all the grains are mixed ready for you to crush it is going to cause issues. There is a bigger variation in the size of the kernels at the moment, making setting the mill tricky.

 

[The Baron]

I think you have already sussed it Gareth as long as you have done the usual Hydrometer refractometer checks.
Boris may have shed some extra light on the grain being new season as well so maybe a combination.
It is unbelievable to be so far out for a experienced brewer, I would also do a Iodine test next time too

 

[Hazelwood Brewery]

If you have an issue with the crush of your grain (too coarse) then you will find that by mashing for longer you still reach the intended OG. This is just a question of surface area.

If you’re following a recipe it’s unlikely you’ve tried to mash without enough diastatic power.

Mash temperature and mash pH are certainly possibilities but you have to be quite a way off.

I’m assuming you’re not confusing measures eg Kg vs lbs, litres vs pints. No offence intended here

 

[Agentgonzo]

If you have an issue with the crush of your grain (too coarse) then you will find that by mashing for longer you still reach the intended OG. This is just a question of surface area.

If you’re following a recipe it’s unlikely you’ve tried to mash without enough diastatic power.

Mash temperature and mash pH are certainly possibilities but you have to be quite a way off.

I’m assuming you’re not confusing measures eg Kg vs lbs, litres vs pints. No offence intended here

The grainfather recirculation should help a lot of completing the conversion

Given it was a GH recipe I'm assuming it's not the recipe that's causing it.

 

[borischarlton]

I would suggest that you have not taken into account the new seasons malt and just how different in size each kernel is. We have seen a massive variation this change over. Most of the malt, the kernels are much bigger requiring a larger gap, conversely we have also seen the opposite in some malts. Changing mill settings is a constant for us but "home type" mills are a little more forgiving but I bet that is the cause.

Plus, if you are receiving uncrushed grain bills, where all the grains are mixed ready for you to crush it is going to cause issues. There is a bigger variation in the size of the kernels at the moment, making setting the mill tricky.

This explains it a little better
https://www.themaltmiller.co.uk/blog/brew-with-us-essentials-02/

 

[Yabezag]

Thanks for all the inputs. I will check the milling. Three versions of recipe Brewfather, Grainfather and what I bought! EBC are different is the only thing I noted.
I will check the temp vs the controller and already cross checked my refractometer vs hygrometer.
I also attached the Grainfather snapshot as I re-entered the ingredients off the supplier label.
The only other thing I can think of is that the ppg values are different from the assigned ones the recipe tools use.

 

[Hazelwood Brewery]

The grainfather recirculation should help a lot of completing the conversion

Not necessarily. I recirculate through the mash and after cleaning my grain mill I forgot to reset the gap. My next mash took four hours even with recirculation.

Given it was a GH recipe I'm assuming it's not the recipe that's causing it.

Yeah, that’s my assumption too but I’m always a bit wary of assumptions

 

[The Baron]

I have looked at both recipes and they look fine to me so its not the recipe as enough conversion malts the only thing is they have got 75% eff and some of it maybe that you have not reached that but to get such a low SG your eff/conversion must be way off.
Have you double checked the Hydrometer etc yet

 

[Agentgonzo]

The only other thing I can think of is that the ppg values are different from the assigned ones the recipe tools use

Unlikely. I've never looked at those values and just picked the grain from the list in the grainfather app. My OG is almost always within a point or two of the recipe

 

[Yabezag]

Unlikely. I've never looked at those values and just picked the grain from the list in the grainfather app. My OG is almost always within a point or two of the recipe

I agree. I looked at other recipes as the Grainfather app needs this value. I just plug in 35 which seems to be the average- at least for the basemalt which will drive most of the OG value.

 

[user 43495]

I am on my 60th Grainfather 30 brew and am occasionally struggling to hit Target OG at end of Mash. I suspect the grain mill as I have not changed anything else. Last night I was doing David Heath’s Mild. Target OG 1.035, I got 1.018. I have spoken to the supplier who delivered 5 grain bills in December. Will see what the next one does!
Any ideas?
Thanks
Gareth

I've never used a grainfather but usually mash efficiency depends on the quality of the malt, the ph of the mash environment, mashing time for sufficient conversion and an efficient sparge. I posted some photos of one of my brewdays here so you can see all my old-fashioned kit but the beauty of it is there's hardly anything to go wrong which cannot be fixed on the spot. I usually get 92-95% efficiency.

 

[Agentgonzo]

I've never used a grainfather but usually mash efficiency depends on the quality of the malt, the ph of the mash environment, mashing time for sufficient conversion and an efficient sparge. I posted some photos of one of my brewdays here so you can see all my old-fashioned kit but the beauty of it is there's hardly anything to go wrong which cannot be fixed on the spot. I usually get 92-95% efficiency.

Wowsers. I've never heard of proper getting over 90% efficiency before. 80 is pretty good, and above 85 it's pretty hard to achieve! Good on you!

 

[user 43495]

Wowsers. I've never heard of proper getting over 90% efficiency before. 80 is pretty good, and above 85 it's pretty hard to achieve! Good on you!

Occasionally it's a little lower but good sparging really helps I find. Batches of malt can vary in extract potential so I feel the brewers ought therefore not necessarily berate themselves. Maybe my old kit enables more tweaks from the brewer? I have never used anything like a grainfather. I saw one on display in a home brew shop and I'm afraid my reaction was "Gosh, look at all those things to go wrong". Also I recall the salesman telling me that one still has to do one's own sparging? If so maybe that's where a lot of potential extract is being lost. I have no experience of these devices so profess no knowledge.

 

[The Baron]

Is that brew house eff or mash eff?

 

[user 43495]

Is that brew house eff or mash eff?

I base it on fermentables put into the mash tun and the OG I get v the amount of liquor used.

 

[The Baron]

so not brewhouse eff but mash eff.
this is usually higher than brewhouse eff which is what most of us brewers use but still impressive