Grainfather low og

[bbreal]

Hi, quick question. Just got grainfather, so far so good. I've done few all grain batches using all grain kits from HBC. I was near the og targets but on the grainfather I'm out a bit. Wondering what's happening. I use grainfather calculator for water amounts. I may be wrong here or I'm thinking are the grains crushed too fine. Any ideas appreciated. Thanks.

[fishjam45 (Colin)]

Too coarse a grain crush your OG more than too fine.  Too fine a crussh should lean you towards hitting or beating your expected OG.
How old is/was the grain you used?
Did you mashout at 75degrees for 10 minutes?
there are a lot of factors that can and will have an effect on gravity, get a few more brews under your belt on the grainfather and you'll start to nail it.

[mick02]

I also find that if you don't set your efficiency correctly on the Grainfather recipe builder or Beersmith then you'll be out.

I would suggest setting the efficiency to about 87% for beer where the grainbill is 5kg or less and work downwards from there (70% for a 7.5kg bill)

That might help.

[bbreal]

I'll give bit more detail, I got all grain kit from HBC, if anyone used these they come with instructions based on using my older equipment, grainfather instructions don't seem to be available. I basically transferred the instructions over to the grainfather, if the instructions said mash for 1 hr at 67 deg C, I used that on the GF. after it says sparge 8 litres at 80 deg followed by 14 litres at 80 deg. (these temp and amounts are examples, can't remember exactly.) I used the GF calculator for this stage. No mash out at 75 deg c.
The grains looked pretty good, not too coarse and not old, got them in the post Friday and used them the following Friday all sealed in bag from HBC. I suppose these kits are aimed at my older equipment, I must just find a way to transfer it over to the GF successfully or just use grainfather recipes specifically. Is there anywhere that has grainfather recipes available apart from grainfather website. Thanks.

[fishjam45 (Colin)]

Am I right in saying you sparged with 22ltrs?
I'd say that could be your problem. A 5kg grainbill on the Grainfather should have close to a 17ltr Mash Volume and a 15ltr Sparge.  If you sparge too much you are only diluting your wort.

What was your preboil volume?

[mick02]

Am I right in saying you sparged with 22ltrs?
I'd say that could be your problem. A 5kg grainbill on the Grainfather should have close to a 17ltr Mash Volume and a 15ltr Sparge.  If you sparge too much you are only diluting your wort.

What was your preboil volume?

I reckon Colin is spot on.

If you get a mash kit and don't know the contents then just weigh the grain. Using the weight alone you should be able to calculate the correct mash and sparge volumes for the Grainfather.