Take the 2-minute tour ×
Homebrewing Stack Exchange is a question and answer site for dedicated home brewers and serious enthusiasts. It's 100% free, no registration required.

Imagine this scenario: you have a an extract recipe that contains a pound of steeped caramel malt. According to http://www.promash.com/FAQ/faq_diff.html the average efficiency of steeped malts is around 30% (as steeping is mostly for color/flavor), so you can calculate the GU potential and take 30% of that for the original gravity estimate. Essentially GU = PPG * weight / gallons * efficiency.

Now imagine I change the recipe, and use pale malt as a base instead of the extract turning it into an all-grain recipe. I assume at this point I would throw the caramel malt in with the mash, which has an average efficiency of something like 75%. Does that mean I take 75% of the pale malt GU and 30% of the caramel, or 75% of both?

In other words - does the act of mashing rather than steeping a caramel malt cause the efficiency to change, and if so to what degree? I am looking for a way to calculate the estimated original gravity while taking efficiency into account.

share|improve this question
add comment

1 Answer 1

up vote 3 down vote accepted

There is an efficiency difference - while a lot of the starch in caramel malts have been converted, there is still some remaining that can be extracted in a mash, but not in a steep. Also, the mash is typically done for longer than a steep, plus a sparge, which extracts more sugars from the grain. 30% extraction for a steep seems on the low side - but let's go with that for now.

In principle, if you were getting 30% extraction but now get 75%, then you would need to use 30/75 = 40% of the original 1lb of speciality malts to arrive at the same gravity. But doing that means you are going to lose a lot of color and flavor, that being the main contribution from the speciality malt. Instead, to preserve the color and flavor, keep to the 1lb of speciality malts and adjust the quantity of pale malt to account for the increased GUs from the speciality malts.

So, how many additional points from the speciality malt are you getting with the increased efficiency? Assuming your 1lb of speciality malt is a mainly mix of caramel malts, which have a typical yield of 35 points, then you'll now get 35*0.75 = ~26 ppg compared to 35*0.30 = 10.5 ppg from the original efficiency. Scaling that to a 5 gallon batch, that's about 5 points vs. 2 points, so you'll gain an additional 3 points with the increased efficiency in the mash.

To hit the same OG as the original recipe, you then reduce the amount of basemalt so that it produces 3 points less.

Brewing calculators, such as Beer Calculus make this process a lot simpler.

30%?

30% yield from steeping does seem a little low to me - 50% is probably a better estimate of typical steep efficiency across all malts. In practice it varies for each malt type.

For example, caramel 40L has a typical potential extract of 35 points. John Palmer reports that after steeping caramel 40L he gets 22 points, so an efficiency of 22/35 = 62%. That's the best efficiency reported for the malts tested and is because most of the starches are already successfully pre-converted during the special malting process used to produce these medium crystal malts. The efficiency of dark crystal and chocolate was lower - 45% and 42% respectively. Averaging all of these (taking typical quanities into account) gives about 50% which is often quoted as the typical extract from steeping.

share|improve this answer
    
Wow thanks @mdma for the thorough reply and the link to John Palmer's steeping info. I'm actually working on a calculator similar to Beer Calculus at Malt.io so I'm trying to make sure I properly approximate the GU contribution based on steeping vs. mashing. The Typical Malt Yields table on the same site is particularly useful for seeing the difference for caramel malts when mashed vs. steeped. –  Daniel Sep 9 '12 at 15:46
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.