Adventures in Cheesemaking

Adventures in Cheesemaking

February UCN 2015

By Gayle Tanner

Bonnie Blue Farm is a licensed dairy in southern middle Tennessee owned and operated by Jim & Gayle Tanner.

Jim & I moved from No. CA to Wayne Co. in 1999 bringing 11 goats, 2 dogs and all our worldly possessions. We built the dairy and were licensed by the TN Department of Agriculture in 2006 and at the time we were the only goat dairy in the state. We produce all of the milk for our farmstead cheeses from Nubian and Saanen dairy goats. The milking does number between 35 and 45.

In our micro dairy every drop of milk is important in both quality and yield. Production and components for each doe are reported on our monthy DHI milk test forms and used for assessment and management in addition to annual linear appraisal scores. With cheese demand high I’ve been told, “You need to milk more goats.” There’s only so much time and milking more does is not my goal – I would much rather milk fewer does with more ‘cheese’ milk.

In 2011 I became aware of a genetic test for alpha s1 casein available through ADGA. We started submitting hair samples for testing in July 2011. Nearly four years and some 80 tests later we have a dozen milking Saanens that carry the coveted ‘B’ allele with many more freshening in spring 2015, some will inherit the higher yielding alleles from both parents.

On December 25, 2014 there was enough time and milk to try a cheese yield and flavor experiment comparing the milk from Saanen does with the B allele and those without.

For those unfamiliar with alpha s1 casein this is the text from ADGA explaining its properties:

The alpha s1-casein is a protein polymorphism of goat milk first described in Europe, in the French Alpine and Saanen breeds, in the early nineteen eighties, and is one found in all dairy goat breeds.

These polymorphisms have been found to affect cheesemaking due to differences in protein content, renneting properties (faster coagulation and firmer curd) and a possible connection in relation to cheese flavor. In one study, the results of researchers conducted on homozygous individuals for the various alleles confirmed the effects of genotype on the casein content in milk by showing the cheesemaking yield observed in milk produced by those animals with strong alleles was 7% higher in comparison with those with medium alleles and 15% higher than those with weak alleles.

Knowing the specific genetic polymorphism at goat casein loci on breeding stock would allow the breeder to set up breeding and selection programs targeted towards the improvement of cheesemaking yield by selecting for high expression alleles, or selecting for animals with low levels which may be of benefit to those with milk sensitivities.

A report from Veterinary Genetics Laboratory located at University of California, Davis would appear as follows with animal information:

ALPHA s1 CASEIN A/E

Interpretation of result code:

This test is designed to detect three variants of alpha s1 casein (E, F and N) that are associated with reduced content of this milk protein.

Variants, A and B, which represent several known alleles, are associated with a high content of alpha s1 casein in milk. Variants, E, F and N, are associated with a lower content of alpha s1 casein in milk. Any combination of A and B variants will produce high amounts of alpha s1 casein. A combination of A or B variant with E, F or N variant will produce intermediate amounts of alpha s1 casein. Any combination of E, F and N variants will produce low amounts of alpha s1 casein.

The animal named on the report, if a doe, would be expected to produce intermediate levels of the casein and pass on either the A or E to their offspring. If a buck, he would have daughters that would inherit either the A (high level) or E (lower level). The variant inherited from their dam would determine whether they were an intermediate or high level producer of casein.

The Journal of Animal Science research paper titled

Prevalence of {alpha}s1-casein genotypes in American dairy goats

published on-line July 31, 2009 can be accessed through this web site:

http://jas.fass.org/cgi/content/full/87/11/3464

Our first three does with the ‘B’ variant – Birdie, Bailey & Bluegras

Cheese yield

I made two small batches of chèvre, one from the non alpha s1 casein Saanen milk (E/E) and the other from alpha s1 casein (B/E) Saanens. I used the same mesophilic culture and rennet as our normal make for chèvre and incubated for 10 hours at about 74° with a final ph of 4.52 for the non and 4.59 for the ‘B’.

The whey accumulated on the surface looked the same for both but after removing the free floating whey the curd looked completely different. The cheese from the E/E weaker allele Saanens had small open lines filled with whey and when scooped the curds were very loose and mixed easily with the whey – definitely weaker body and not bright white.

The higher allele B/E alpha s1 casein cheese had a perfectly satin smooth, very white surface and when scooped the curds had the texture of firm store bought yogurt – the kind a spoon stands up in. This looked like the chèvre I’ve been seeing in our normal production using the combined milk from all the Saanens and Nubians. The milk at this time of year is late lactation which is usually higher in components giving higher total yield than during our humid summer months. There were several batches of chèvre during the summer of 2013 that had incredibly low yield but not in 2014 with the addition of the first freshening alpha s1 casein B/E does. I knew something different was happening with the milk as feed and management had not changed – only the new does contributing their milk.

The curds were placed in cheese bags and allowed to drain overnight. The next morning they were put in the refrigerator and 12 hours later the curds were weighed.

Non alpha s1 casein milk / alpha s1 casein milk
13.98# of milk / 13.90# of milk
2.33# drained curd / 3.02# drained curd
15.95% yield / 21.73% yield

The increase in cheese was 5.78% - not quite the 7% increase in the study but still substantial enough to be very encouraging especially since the Saanen milk was from B/E does. It will be exciting to try this experiment again when B/B does have freshened. Our normal cheese yield from all the does averages around 17% with some fluctuations depending on time of year.

Cheese Flavor

The next and nearly as important part of the test is flavor. How does this chèvre compare in taste? What if the resulting curds do not have the wonderful texture and flavor we’re used to? This is much more difficult to judge as it is subjective and everyone’s tastes are different.

So who best to get opinions? The people who make a living tasting and preparing food – Chefs! For the ‘taste test’ I mixed each batch of curds with sea salt and made samples for Jim to take to the restaurants and stores that use our cheese. The chefs were willing participants and were intrigued by our genetic project. For the chefs it was unanimous – the alpha s1 casein milk cheese had better texture and over all flavor. Farmers’ market customers had mixed preferences. The differences were subtle – not nearly as definitive as the quantitative yield increase.

This unscientific but practical experiment has confirmed in my mind the findings in the JAS report. Now I may be able to achieve the perfect balance of keeping and milking does that will produce more milk that not only yields more cheese but enhances flavor. The frosting on the cake is that it is made by wonderful Saanens. One more reason to love our white beauties who quietly prove their value to the goat industry.