BIAB Water v ABV

[ErsteBrau]

Hi All,

I am calculating the amount of water I need for my BIAB brew (I'm just on my second batch). I've found out roughly the amount of water I need, including trub, boil off rate, grain absorption etc. I also know my target ABV, gravities and the brewhouse efficiency but I may want to alter my strike water.

My question is, depending on how much water I have, how will this impact the ABV and OG? For example, my efficiency is 75% and intended strike water is 34 litres, so how can I ensure I hit my target OG (which is 1.062)?

Thanks!
Doug

 

[Norselord]

Hi All,

I am calculating the amount of water I need for my BIAB brew (I'm just on my second batch). I've found out roughly the amount of water I need, including trub, boil off rate, grain absorption etc. I also know my target ABV, gravities and the brewhouse efficiency but I may want to alter my strike water.

My question is, depending on how much water I have, how will this impact the ABV and OG? For example, my efficiency is 75% and intended strike water is 34 litres, so how can I ensure I hit my target OG (which is 1.062)?

Thanks!
Doug

I don't know the answer to your question, but i do know the answer to a different question:

What can i do if my post-mash gravity is lower or higher than it is supposed to be?

If your post mash is lower, you can do one of two things:
1) you can add dry malt extract. One lbs adds 45 points per gallon (1.045), or 1lb adds 9.2 pts per 5 gallons. Be sure to pick the right DME for your recipe...
2) you can boil longer, depending on your boil off rate you can figure out how much longer to boil to evaporate water away.

If your post mash gravity is higher, you can add water. Water has zero gravity points, so if you had 5 gallons at 1.070 and it needed to be 5 gallons at 1.060. You would add 3.2 quarts of water. Because you have added more water, your hop utilization will be off. You should, after mixing, also remove 3.2 quarts of water if you don't want to adjust your hop additions.

Remember that your post mash temperature is going to be really warm, so you must use a refractometer or do a temp. correction with a hydrometer.

 

[Morrey]

Hi All,

I am calculating the amount of water I need for my BIAB brew (I'm just on my second batch). I've found out roughly the amount of water I need, including trub, boil off rate, grain absorption etc. I also know my target ABV, gravities and the brewhouse efficiency but I may want to alter my strike water.

My question is, depending on how much water I have, how will this impact the ABV and OG? For example, my efficiency is 75% and intended strike water is 34 litres, so how can I ensure I hit my target OG (which is 1.062)?

Thanks!
Doug

The OG you start with results from a certain amount of grain releasing a certain amount of sugars ( this includes efficiency) in a pre-determined amount of water. If any of these values is altered, your OG can fluctuate.

Your calculations/recipes are based on a certain volume of water. If you have less water with all other values remaining consistent, your sugars will be more concentrated and the OG is higher meaning you'll have a higher ABV beer. If you have more water than is called for, the sugars are less concentrated, your OG is lower and your ABV is lower. You also need to understand yeasts since some attenuate (ferment) to a higher level. We could take the same OG wort from the same batch, split in half with different yeasts, and have different ABV beers.

If you are familiar with calculation programs, I use BeerSmith which allows me to see all the things you are asking about by playing with water volume, grain amounts and efficiency percentages. If you have less volume after boil than you expected, add water as a top off. If you have more volume than you expected after boil, continue your boil until you have evaporated the excess water. If you focus on OG, the ABV comes right along with that so keep OG as your main focus.

 

[thekraken]

(oops, delete)