Mashing query

[gnorwebthgimi]

After a brief hiatus I'm back brewing this weekend. I've been busy cleaning everything that was mothballed until I sorted the garage and I was thinking about my processes etc. and thinking about the equipment I would like to upgrade.

I am considering the doughing-in part of the mash. I have been adding the grain to the tun then topping off with water at a determined strike level. I consistently get a couple of gravity points below target final gravity (using Beer Engine, thanks Graham Wheeler!) irrespective of yeast used. The only time this didn't happen was when I miscalculated the strike temperature and the mash read at 75'c (167 F). I used cold water to bring this down to 68'c (155 f), which is my usual range (give or take). The beer turned out fine and at the expected target gravity. I suspect that incorrect thermometer readings may account for the lower gravity and I'm actually up to 5'c lower than the stated mash temperature.

However, my theory is that if I add the water to the tun first then add the grain I will denature a higher amount of the enzymes that work at the lower mash temperatures as the grain cools the strike water rather than heats up the grain to the mash temperature.

Do you add grain to water or water to grain in the mash tun and do you get a consistently higher or lower final gravity?

[yojimbo]

Hello

I have always put the water for the mash in the mash tun at strike heat and never had a problem with gravity.

When you addedd the cold water to bring the temperature down this would have given you a thinner mash this could have allowed a better conversion in the mash .

[Wonkydonkey]

There are a few ways to do it. I mostly add water to tun then grain on top. Which the strick calc is good way to determine the temp you need.
Sometimes I dump the grain in and underlet the water, via a siphon tube going into the bottomot the tun. Personally I don't really like this way ( although there's less dust) as I find it hard to give it a good stir. I also find it seems to have hot spots for a longer time. But the beer still comes out fine

I don't think the inial temp matters to much for a few mins ( within a few degrees ), but the higher you go the closer you get to denaturing it (77c). And yeh thermometers need calibrating, which its best to try and do it at 0c, 50/60c and 100c but having said this the boil temp can vary abit depending on the atmospheric pressure. I had a good rolling boil at 98c when it was thundery the other day. But I think my thermometer is about 1c out at 100

So I'd calibrate the thermo, and use the strke calc, and if you were mashing a bit low you would have had thinner beer/less sweet..

I'm sure someone else will give you there view.

[gnorwebthgimi]

Thanks for your responses so far.

The additional cold water was about about a litre and didn't significantly dilute the mash. However, I would have expected a thinner mash to take longer to convert or yield a lower gravity if halted before complete as the amount of enzyme is more diluted in a thinner mash.

I have tried under letting before but had issues with dough balls and it took lots of extra work to mix the mash. On reflection this means I have tried water in first and second and didn't record any difference in final gravity myself but I have only tried water in first once.

[Goulders]

Why don't you stick to one method and work out your mash efficiency? If it is the same over a few mashes then you can adjust your recipe. Beersmith will calculate this, but you can also do it by hand, as below. If you look at your brewing records, you may be able to work this out. The extraction figures can be found from the maltsters:

For example

Pale malt: 3.5 kg @ 293 L.deg per kilo = 1025.5
Biscuit malt: 0.5 @ 273 = 136.5

Dark crystal malt: 0.25 kg @ 275 = 68.75
Chocolate malt: 0.25 @ 273 = 68.25

wheat malt: 0.25 @ 296 = 74.0

Total potential extract 1025.5 + 136.5 + 68.75 + 68.25 +74.0 = 1373 litre.degrees

If runnings from the mash were 24 litres at 1.046 Specific Gravity (ie pre-boil): 24 litres x 46 degrees = 1104 litre.degrees

Mash efficiency would be:
1104/1373 = 0.804 = 80%

Post-boil example:
17L @ 1.056 i.e 17 x 56 = 952 and 952/1373 = 0.693
That is 69.0% which could be called brewhouse efficiency.

[gnorwebthgimi]

Hi Goulders

I have calculated my efficiency of each of my beers, I have noticed that below at around 5KG of malt I get around 70-75% (and sometime up to 80%) but at around 6KG of grist I get a noticable reduction to around 65-70%.

I base my recipes on a brewhouse efficiency of 75% at 5Kg of Grist and 70% at 6Kg.

[Goulders]

The brewhouse efficiency should be lower than mash efficiency because of losses to hops, boil etc.

Why don't you set your process up at 65% (grain doesn't cost much) and then you can liqour back if necessary to hit your target OG?

[gnorwebthgimi]

Thanks Goulders,

I'm not sure I fully understand how mash efficiency would impact final gravity and it may be delving a little deep at this stage. but i will make a note to consider this in more detail in future.

[charliemartin]

I have had similar experiences with FG being lower than predicted by Beer Engine. However, I suspect it may be down to my fermentation side of the process. I do not have temperature control yet and I don't accurately calculate how much yeast I pitch, so may be overpitching occasionally. I am not sure how BE calculates attenuation rates, but since there is no input for yeast or mash temperature, I would guess it just uses a set figure. Without checking any figures I would suspect something like 75% apparent attenuation. So depending on mash temp, fermentation temp, type of yeast, length of fermentation, you may have a different final gravity than BE predicts. I always calculate my apparent attenuation to give me a better idea what my FG will be with a particular yeast with a particular mash temp and fermentation temp. (ferm temp is still a bit variable, but planning a brewfridge soon).
Cheers,
Charliemartin

[rpt]

I don't think any software will accurately predict FG as there are too many variables.

[AnthonyUK]

Thanks Goulders,

I'm not sure I fully understand how mash efficiency would impact final gravity and it may be delving a little deep at this stage. but i will make a note to consider this in more detail in future.

Mash efficiency is not linear as you have noticed. As mentioned, you'll need to do a few batches at various gravities to work out the best settings for your equipment.