Grainger, Was the retained wort weight figured in the mashout weight of the grains?? check the discussion about this at http://www.biabrewer.info/viewtopic.php?f=5&t=1503

To quote PistolPatch from the topic "With traditional brewing, you'll lose about 1 litre for every kilo of grain mashed. In BIAB it should be more like 0.6 to 0.7 litres"

How do you find those threads joshua .

Graingers, post #8 in that thread is the key so I'll just copy it here...

This is one of those weird areas of brewing. Your numbers above which work on weight, would lead you to believe that you lost basically no volume in the lauter however this is not the case.

On your next brew, instead of weighing the bag, measure your volume into the kettle. In other words, all the water you get after the mash including what you drain from the bag. Then subtract this from all the water you put in. For example...

38 L (at mash temperature) before grain added - 35 Litres (after bag drained) = 3 litres

If you had used 5 kgs in the mash, your liquor retained by grain would be 0.6 L/kg.

If you like, also weight the bag and you'll find that the drained bag will weigh just a bit more than the initial grain bill - just like you found above.

It's a weird area and hard to explain well. The best I think I can do is give the analogy of a glass full of marbles. If I added sand to the glass full of marbles, the glass would now be much heavier but the volume remains the same.

To cut a long story short, don't weigh, just measure the volume.


PP

What is basically going on here is when you add the bag into the strike water, an exchange takes place. Sugar from the grain moves into the water and water moves into the grain hulls. Sugar is denser than water though so you can't use weight to work out your volume loss from lauter.

Volume loss from lauter must be determined by measuring volume, not by weighing your bag.

Graingers, Don't forget the wort expands at mashout, around 0.2-0.4 percent from the strike temperature.

Good find, joshua. I read that whole thread.

I did a simple experiment yesterday with hops, not by weight but volume. I took my 8 ounces of spent hops that was fairly dried from the previous day and put them in a half gallon glass jar. They took up nearly the entire volume, but I poured 26 ounces of water in there to make up the half gallon.

What can we say about hop volume, did the 8 ounce of pellitized hops take up 38 ounces of volume?

MS, That is another variable that happens.

That is also why I Squeeze, Squeeze and Squeeze again!

Graingers wrote:This makes such common sense... Feel a bit stupid for not realising it before. Ok, so the short answer is, measure it thru the volume over the next few brews and try again...

I wouldn't feel stupid Graingers . Myself and many others have done exactly the same thing.

And yep, next few brews, take those volume measurements. The default used in BeerSmith comes from this site and is based on figures we collected from a number of brewers. Don't expect to perfectly match the default as it will depend on many things.

You will find it hard to match your numbers to BeerSmith as there are a few pitfalls you will have to discover and then work around in the program. It is also very easy to make mistakes by hitting a wrong button. To find some of these problems will take you a lot of study and a lot has been written on this here.

Because of the above (more details here), BIABrewer decided to come up with something that would be fast to learn, safe, powerful, accurate and intuitive. The BIABacus is the result of this and whilst it is still only in spreadsheet form, it satisfies the above requirements already to a high degree.

A first look at it* you may find intimidating as all the critical information is on one sheet however there is a logic to the layout that doesn't take too long to learn. A lot of things in the BIABacus are revolutionary so don't 'trip' over it just because it is a spreadsheet.