Has anyone noticed recently that the Grainfather on-line site is giving odd values for strike water? Normally the mash has a porridge like consistency. Today I did a brew and just blindly followed the value for my strike water. It was very runny and I achieved a gravity of 1.038 (target 1.050). My fault, that I should have double checked the values. I have the mash thickness set to 2.75 L/kg. With a 6.1kg grain bill it should be 16.1L, but grainfather is telling me to add 20.27L strike water. Any other grainfather users noticed this?

Are you including the 'dead space' volume in your calcs? The instruction manual tells you to allow 3.5l to account for the liquid below the bottom of the grain basket.

I have set 3L loss along with the recipe. The thing is that if the grainfather website is adding on the deadspace amount to the strike water, then surely this is wrong. It should be added to the sparge water?

For 6.1 kg of grain, you need 6.1 x 2.75 = 16.77l of water in the grain basket with the grain, plus the 3.5l near the pump filter below the grain basket = 20.27l. The sparge water calcs include the boil losses and the grain absorption losses.

What Mmm says. Never had any trouble. I've read a lot of debate on this matter and what I learned was just follow the book. So I do.

Hi your experience is odd, but I find the grainfather instructions manual equation method better than the website. The website and equation mostly match upto 8KG then you get some differences with the website calculation. Also I find the website suggests one litre more sparge water than the manual method. In your case the website and manual method both give the same 19.97 litres of mash water based on 6.1KG grain. They use the same calculation which is (grain bill x 2.7) + 3.5. I can't see why you thought it should be 16.1 litres, that seems too low. The manual method does not use length of boil in either mash or sparge calculations, you have to input based on your experiences/set-up. For me the boil off rate averages at 1 litre per half hour, adding to that the standard trub etc losses of 2 litres and a 60 minute boil I will loose 4 litres in total. So with a 23 litre batch, I will loose 4 litres. Hence the manual method calculates enough sparge water to reach 27 litres pre-boil volume. Consistently I find by letting the sparge process finish completely, including a stir to get the last of the wort out, that I get almost exactly the pre boil volume of the manual calculation. Now I just go with the manual method because it is spot on. Last weekend I made an IPA, using the grainfather recipe tools, the expected pre-boil volume was 27 litres and once again it was exactly 27 litres. Expected OG was 1071 and I got 1072.

I've previously played around between the GF calcs page and cross ref'd it to manual. Soon learned to always trust the manual. I'm not a connect user, BTW, found I don't need it. Had a lot of trouble tho' reaching my 23 litre fermenter volume, always short. Eventually found that if I come to the boil at 30 litre volume, 1 hour boil gets me down to about 26/26.5 litres on the scale. Take out 23 litres, measure the remainder, about 1 to 1.5 litres. This tells me that at end of boil what appeared to scale at 26/26.5 litres was actually less. Expansion takes up a lot of space. Sometimes, not always, at end of sparge I have to add 1 litre of water to reach 30 litre mark.

Very similar to my experience. Done 17 brews on the Grainfather and I need 30l at the start of the boil to get 23l into the fermenter. It's no big deal, I always hit the recipe targets. I've given up wondering why other people don't need this much. The beer tastes great and that's all that matters at the end of the day.

Yeah the online tools are a bit useless at the moment, I had a big discussion with the support team / developers which didn't go anywhere as they basically just said "no, we're right" and I gave up. The losses box on the recipe should be set to zero if you are entering brewhouse efficiency, they've messed up the formulae and double account for the kettle loss. The mash and sparge volumes are also hit or miss as they'll randomly change, I generate my recipe and make a note of it in my book for water treatment, when I go and do the brew and generate the online brew day the sparge is generally a few litres less. I use the formulae from the book: 2.7 L/kg + 3.5L for mash, then sparge enough to hit a pre-boil volume 5L above my FV target for a 60 min boil, 2L for kettle loss and 3L/hr boil-off, I find that grain absorbs 0.8 L/kg, so the full calc becomes: FV + 5 + (0.8* kg grain), I'll add an extra 1.5L if I'm doing a 90 min boil. Then to make matters more complicated, I do 15L batches as standard and I find I get better efficiency if my sparge volume is roughly equal to the mash volume so quite often I'll reduce the mash to 2.3 L/kg which increases the sparge, this was a tip from their blog about baltic porter which was about 18 months ago now. This makes a thicker mash, but not too thick and it does help my efficiency. Hope this makes sense.

As far as water volumes are concerned: The mash volume calculated by Grainfather will be about identical to many other calculators. Because there isn't many variables to play with - just three, the amount of grain, the grain absorption, and the mash tun deadspace (which is about 3.5L - sometimes see the US unit conversion of 3.41L - for a Grainfather, and this is "recoverable" because the mash tun is the boiler so it isn't a mash tun "loss"). But things get more interesting calculating the sparge volume because there are lots of variables and lots of opinions. I had to learn this trying to adapt Beersmith calculations to Grainfather's. Most previous adaptations tweaked variables that affect both mash and sparge water calculations so the result is always a compromise. My own solution tweaked the Grainfather software's otherwise unused "sparge/lauter tun loss" variable so its calculation is forced to match Beersmith's. The difference between the two calculations, while seemingly randomly skipping between limits, seemed to always be less than 1L. But going back to the OP: I presume by "strike volume" it means "mash water volume". Because a Grainfather has no concept of "strike" (temperature). But the software can be tailored for situations other than with a Grainfather so "strike" appears in the GF software.