Author Topic: Potential / Yield Questions  (Read 3549 times)

Offline docmckee

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 4
    • The Zymurgy Guide
Potential / Yield Questions
« on: March 05, 2012, 02:05:20 PM »
I'm playing around with BeerSmith for designing a mead, and am planning to use Alexender's grape juice concentrates as part of the recipe.  I want to use BeerSmith to compute an estimate of my gravity to hit a target ABV.  This had led me to a couple of things to ponder.

First, under the ingredients screen, there are boxes for 'potential' and 'yield."  My thinking was i could put in the information for the concentrate and add it as a new ingredient.  Alexander's tells via the can label that the concentrate is at 70 Brix, which converts to a SG of 1.355.   I'm not sure about the math here if i dilute that down to a five gallon batch.  Given that i have a 4 pound can, can i just (assuming 5 gallons weighs around 40 lbs) get a divisor by dividing 4/40 to get 10 percent of weight, then divide my gravity points by 10 to get a potential of 1.034? 

Yeild is my other concern.  I am assuming that yield is brewhouse yield, which would be what percentage of total possible dissolved solids would end up in the wort/must.   When I see that sucrose has a 100% yield, I think I am correct.  75% is a thus a good guestimate for most LMEs because we can assume that the maltster has a brewhouse efficiency close to that.    When I see that Honey has a 75% yield, I am confused.  I always thought the fermentability of honey was VERY high, as it is almost pure sugar.  Are there really 25% of the weight of honey tied up in unfermentable solids? Or am I missing something (most likely option!)?     

Offline Myk

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 155
Re: Potential / Yield Questions
« Reply #1 on: March 05, 2012, 03:29:08 PM »
No math needed.
Put the brix in the yield box.
I don't know what "yield" means but I know it equals the refractometer reading, which is brix.
BTW, all the 4lb Alexanders I'm seeing pictures of say 68 brix.

Yield has nothing to do with fermentability.
Honey is a strange creature. It ferments sweet or dry depending on a lot of different factors. It seems to be pretty predictable if you get the same honey, use the same ingredients and the same process.
Otherwise if you change honey suppliers, yeasts, sometimes add nutrients or sometimes don't you can have the honey go from 80% fermentable to 100%, you can have a 14% yeast take it to 16% or you can have an 18% yeast crap out at 12%.
Different honey also has different sugar levels. I've had a yield of 76% work better for predicting my cyser recipes with the honey I've used.

I'm not sure if the grape in a pyment would supply enough nutrients because honey supplies none. You would be best off using nutrient and plan on it going dry (anywhere from bone dry .99X to barely sweet 1.003-ish). Backsweeten after it's dry and stabilized (sorbated/sulfited), it's just easier to control the final product that way.