Grainfather Recipe Creator and Efficiency

I was wanting to discuss something as a bit of a sanity check but don't feel comfortable doing it in the very public GF facebook groups.

Recently the GF recipe creator got some tweaks made and when you edit an old recipe your OG drops to about 90% of it's previous value. I asked about this an they said it was a known bug and were working on it then confirmed that now their formula takes post-boil losses into account so it looks like this.

OG = Total gravity points * efficiency / (batch size + losses)

So for a standard batch of 23L + 2L losses, it's now working out OG based on 25L instead of 23L so giving a lower OG. As far as I can tell this would be correct if you used mash efficiency but the info box says it's brewhouse efficiency that should be entered and as far as I'm aware this takes all losses into account.

I did a quick check on their maths assuming it was correct, I adjusted my brewhouse efficiency to match my original OG then back calculated mash efficiency. Somehow I doubt I got 97% and 99.7% mash efficiency on my 2 most efficient batches.

I send them back an email explaining this about a week ago and today I received an email which largely says "no we're right" stating that OG should be based on the post-boil volume as that's when it's locked in. There's an easy fix in the recipe section, we can set losses to zero then it all goes back to normal but it's still annoying.

Sorry if this is a bit of a rant but I'm trying to make sure I'm not doing something daft, and if I am then somehow i'm getting BH efficiency of mid to high 80s which is pretty cool, but I don't believe it. :-)

Have you tried comparing the GF results with the BrewersFriend recipes above?

I use BF regularly and find the result to be "just about where I expected them to be".

With regard to ".. the post-boil volume as that's when it's locked in ..." does the GF system calculate that, after "post boil", the volume is usually made up to the "fermenter volume"?

In my case the 28-30 litres of wort I start with in the Boiler may very well be reduced to 20 litres by the time I have ...

• Boiled it with a "rolling boil" for 60+ minutes.
• Removed the Hop Bags and the wort contained within.
• Left behind a litre or two of "debris" in the Boiler.

... but I only take the OG after I have made up the volume to 23 litres and before adding any Yeast Nutrient or Yeast.

So far, the OG has been within a couple of points of the prediction made by the BrewersFriend calculator. :thumb:

Good plan, I've not compared it in another site yet, but will do that now.

GF system as about 2L dead volume so for my regular batch of 15L I should have 17L after the boil and due to a 3L/hr boil off I'll sparge to collect 20L total pre-boil, been working so far and I generally hit 75% efficiency +/- a couple of points provided I'm not making a high OG beer where the efficiency as dropped as low as 66%.

Update - Just put the details for my bitter into Brewer's Friend and it agrees with the previous version of the GF formula and if I change my batch size to the post-boil volume then it agrees with the new one. So definitely looks like they've messed up and don't seems to see it.

"There's none as deaf as them that don't want to hear!" ...

... as my Mum used to say! :thumb:

I use the GF recipe builder and water calculators, though I have a Bulldog Brewer. I've always found the OG to be within a point or two - I used it last weekend and it was still within a couple of points so unless they changed it in the last few days it's still accurate for me.

I hadn't noticed that the OG calculation had changed but I have noticed that the FG calculations seem to be off by quite a large margin on a couple of recent recipes when compared to what I actually calculated manually. The GF recipe creator is predicting an attenuation of 85% on a recipe with only Maris Otter and Imperial Malt. I've never got more than 75% on anything I've brewed unless there's sugar involved.

@Linalmeemow Changed a couple of weeks ago now, go back into an old recipe and hit edit, you should see the OG drop. Then set losses to zero and it should go back again. Glad it's been accurate for you, it's been good for me too.

@rank_frank FG depends on what you put in for mash and yeast, my brews generally come within 2 points if not bang on, since I'm reusing yeast I think I'm slowly getting higher attenuation so have to adjust my figures. I use Wyeast yeast and enter the mid-point of their expected attenuation range which seems to match the apparent attenuation when the mash is 67.5c. You're mash temp will then adjust the apparent attenuation it predicts. You must be telling it a very high attenuating yeast with a low mash temp. I brewed with Wyeast 1728 Scottish Ale once and hit 86% apparent attenuation, despite it having a stated average of 71% I had to increase that to 82% to get the figures to match, online research backs that up, stated to be a low attenuator but in practice hits 80%+ with most brews.

@Zephyr259 It's neither a high attenuating yeast or a low mash temperature. I'm looking at my most recent and recipe it's this :

5Kg Maris Otter
1Kg Imperial Malt

losses 2L

90 minute mash at 66C

100g Fuggles at 90 min boil
20g Goldings at 15 min
12g Goldings dry hop

Yeast Safale S04, 75% attenuation

The Recipe Creator shows OG 1061 and FG 1010. I calculated and actually got OG 1061 FG 1015

Zephyr259 said:

@Linalmeemow Changed a couple of weeks ago now, go back into an old recipe and hit edit, you should see the OG drop. Then set losses to zero and it should go back again. Glad it's been accurate for you, it's been good for me too.

@rank_frank FG depends on what you put in for mash and yeast, my brews generally come within 2 points if not bang on, since I'm reusing yeast I think I'm slowly getting higher attenuation so have to adjust my figures. I use Wyeast yeast and enter the mid-point of their expected attenuation range which seems to match the apparent attenuation when the mash is 67.5c. You're mash temp will then adjust the apparent attenuation it predicts. You must be telling it a very high attenuating yeast with a low mash temp. I brewed with Wyeast 1728 Scottish Ale once and hit 86% apparent attenuation, despite it having a stated average of 71% I had to increase that to 82% to get the figures to match, online research backs that up, stated to be a low attenuator but in practice hits 80%+ with most brews.

Click to expand...

Tried editing an old recipe - no changes at all for me.

@rank_frank Very odd, I just mimic'd you recipe and I get 1.056 with the 2L losses and 1.061 when the losses are removed. That mash and yeast give me FG 1.013 which is a bit closer to your actuals.

@Linalmeemow I forgot, there's a bug as of last night and now editing a recipe doesn't change any of the specs... kinda totally buggered now, although you can still make a new recipe, just don't save it til you're fully done.

Tempted to give beersmith a shot if the GF system keeps being buggy. I do like the app, it gets a lot of bad press but has worked fine for me.

Zephyr259 said:

Recently the GF recipe creator got some tweaks made and when you edit an old recipe your OG drops to about 90% of it's previous value. I asked about this an they said it was a known bug and were working on it then confirmed that now their formula takes post-boil losses into account so it looks like this.

Click to expand...

Thanks for posting this.
I thought I was going mad when I came back to the Grainfather recipe generator and all my OGs had dropped.

Now to carefully read through this thread and work out the solution...

MagnusTS said:

Thanks for posting this.
I thought I was going mad when I came back to the Grainfather recipe generator and all my OGs had dropped.

Now to carefully read through this thread and work out the solution...

Click to expand...

No worries, solution is to set the losses value to zero, then it'll work as before. Well, hopefully, it's been a pain today, editing a copied recipe seems to fail when saving then removes all data except name, after a few tests it seems to happen. After editing the hops and even does it when creating a new one.

nothing surprising with the attitude of some of the Grainfather hierarchy people they are obviously wrong there is a problem as you chaps have proved. Good job you did not post on the GF site as they may of banned you in true GF style for daring to say that it is not perfect Lol

This is what happens for me:
Original saved recipe: OG predicted 1.061

Switch to edit mode. No changes made to grain, but now predicted OG = 1.055

Losses changed to zero L (as suggested by @Zephyr259) and predicted OG now back to 1.061

Zephyr259 said:

No worries, solution is to set the losses value to zero, then it'll work as before.

Click to expand...

Thanks for this. Great work-around.

Zephyr259 said:

t's been a pain today, editing a copied recipe seems to fail when saving then removes all data except name, after a few tests it seems to happen.

Click to expand...

Just lost one of my recipes. As you say no data in it after editing and saving. Says it was created by someone call 'Rachel Pickering'. I'm giving up for today.

MagnusTS said:

Just lost one of my recipes. As you say no data in it after editing and saving. Says it was created by someone call 'Rachel Pickering'. I'm giving up for today.

View attachment 16284

Click to expand...

Yep, I get the exact same name. Should probably tell them but can't be bothered right now. :-)

Rachael Pickering sounds like a right party animal, brewing an AG Imperial Stout with 0% ABV!

Same thing happened to me at the weekend, a brew I've brewed 3-4 times before. Post boil gravity has suddenly dropped from 1.050 to 1.045 on their recipe building website. Unsurprisingly it came out at 1.050 (as it usually has before). Obviously it must just be because the moon has aligned with Jupiter and Saturn and not as their website is wrong!

I've now changed my efficiency to 88% from 80% to get the right figures (to be fair is now a more accurate reflection of the mash efficiency I do actually get, so perhaps this now correlates more accurately than before)

The change means that the efficiency you enter is actually your mash efficiency since they are removing kettle losses from the calculation.