Saturday, May 22, 2010

Malt Analysis and potential calculation

Wondering why you are getting that low mashing efficiency, even though you optimized your mash tun design and milling gap?
That can be caused by using the wrong malt potential, specially on the base malts that represent the big chunk on your grain bill.
So after having this same issue for a while, decided to do my homework and investigate the base grain malt analysis from manufactures like Briess and calculate the gravity potential myself.
That in fact correct my efficiency calculations and allowed me to do better OG predictions.
The basic numbers you need to get from the malt analysis sheet are two:
DBCG = Dry basis coarse grind
MC% = Moisture content

The potential in PPG, which is point per pound per gallon would be calculated as:
PPG=46.214*(DBCG/100-MC%/100-0.002)

Example:
Malt "Briess 2Row brewerrs Malt"
DBCG=79.5
MC%=4
PPG=35

How to use PPG?
If your PPG=35 from the example above, that means if you use 1 pound of this malt to produce 1 gallon of wort, you would get 1.035 gravity or OG if your mashing efficiency was 100%.
Your OG can be calculated as:
OG=1+(EF%/100)*(PPG*MW/BV)
where
MW = pounds of malt used
BV = Batch volume in gallons
EF% = Mashing efficiency

or

MW = 1000*(OG-1)*BV/(PPG*EF%/100)


New example:
You want your OG to be 1.050 on a 5gal batch and estimate your mashing efficiency at 70%, so the base malt weight your need is (for Briess 2Row brewers Malt) :

MW=1000*(1.050-1)*5/(35*70/100)
MW=10.2# of malt

I downloaded several spec sheets from Briess.com and calculated each malt PPG. I used mostly Briess malt so here's a table I use:

Click to see it bigger

Friday, May 21, 2010

Brewing a Summer lime Ale

Playing with my recipes here and decided to do a light ale and add some lime zest to see what happen.
Here's the recipe for this batch, which I called "Summer Wit", since it has quite some wheat malt to the grain bill.
-3# Briess Pilsen Malt (1.1L)
-4# Briess White Wheat Malt (2.5L)
-1# Briess Viena Malt (3.5L)
-1# Flaked Rice
-0.5oz Goldings USA for 60min
-0.5oz Goldings USA for 5min
-1 tsp irish moss for 20min
-1 pack Dry Yeast Safale S-04
-Zest from 2 limes, mixed with 1 cup of vodka. Added to Primary.

Mashed at 155F for 60min, here are the brew numbers:
OG=1.043
FG=1.008
ABV%=4.5
Color=4
IBU=10

Bottled at 5/16/10, tasted nice and not overpowered by the lime, at least at that point. Will have to wait all flavors to mellow down to taste it again, but feels it will be a very nice and refreshing beer.

Here's the fermentation profile for the S-04.



Click HERE for the review of this batch.

Thursday, May 20, 2010

Using Dry Yeast

Have used mostly Wyeast smack packs until now and decided to test some dry yeast, mostly to keep some in stock and avoid a trip to the LHBS for every batch I brew, since I always like to get the freshest possible liqui yeast. Got the 11.5g dry yeast from Fermentis, Safale S-04, Safale US-05 and Safale S-33.
I must say I'm mostly not going back to liquid yeast, unless I need a special strain that I can't get in dry.
I got some cool direction on how to re-hydrate the dry yeast and it has worked for me every time, with Krausen formed after 6 to 8h.
The S-04 yeast is a beast, promoting a very fast and clean fermentation, not huge amounts of CO2 so no over spilling thru my airlock. The floculation after fermentation is awesome. The beer left is very clear and after few weeks in bottle conditioned, taste great!
The re-hydration process, which at first looked weird with the higher temperature, is listed below:
1)Once you have your wort ready to picth, at bout 70 to 75F, move to step 2
2)Boil 0.5l of tap water for 5min.
3)Remove from heat and cool to 103F
4)Add dry yeast and wisk to dissolve, for about 3min
5)Cool down further to pitching temp, 70 to 75F
6)Pitch to your wort

There are reasons behind not using sugar water or DME to re-hydrate the yeast, as well as for the high temperature. From what I read it has to do to the fact that the yeast cells do not have the hability to select what comes into the cell on the first seconds of re-hydration, so using sugar water would cause damage to the cells as good and bad thyings will get in. Also, once you get to step 5, the quick you pitch the better, so waiting to pitch actually works against you. The time from step 4 to picth should be about 5min.

So far, S-04 will be my primary yeast for general beers in substitution to Wyeast 1056. It promotes fully fermentation is 48h, has some bread taste while fermenting but it clears out within days.
The US-05 seems to produce fenolics that I don't like, so will probably stay away from it.
S-33 worked fine on my wit recipe and will mostly use it for wheat beers from now on.